diff --git a/README.markdown b/README.markdown
index b3adc1ec4..64db0208d 100644
--- a/README.markdown
+++ b/README.markdown
@@ -379,7 +379,6 @@ The test suite's proto files (i.e. `simple.proto`, `batching.proto`, etc.) curre
 # Todo
 
 - Support the string-based encoding of duration in `fromJSON`/`toJSON`
-- Support the `json_name` annotation
 - Make `oneof=unions` the default behavior in 2.0
 - Probably change `forceLong` default in 2.0, should default to `forceLong=long`
 - Make `esModuleInterop=true` the default in 2.0
diff --git a/integration/simple-json-name/google/protobuf/timestamp.ts b/integration/simple-json-name/google/protobuf/timestamp.ts
new file mode 100644
index 000000000..e4600a73e
--- /dev/null
+++ b/integration/simple-json-name/google/protobuf/timestamp.ts
@@ -0,0 +1,206 @@
+/* eslint-disable */
+import { util, configure, Writer, Reader } from 'protobufjs/minimal';
+import * as Long from 'long';
+
+export const protobufPackage = 'google.protobuf';
+
+/**
+ * A Timestamp represents a point in time independent of any time zone or local
+ * calendar, encoded as a count of seconds and fractions of seconds at
+ * nanosecond resolution. The count is relative to an epoch at UTC midnight on
+ * January 1, 1970, in the proleptic Gregorian calendar which extends the
+ * Gregorian calendar backwards to year one.
+ *
+ * All minutes are 60 seconds long. Leap seconds are "smeared" so that no leap
+ * second table is needed for interpretation, using a [24-hour linear
+ * smear](https://developers.google.com/time/smear).
+ *
+ * The range is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. By
+ * restricting to that range, we ensure that we can convert to and from [RFC
+ * 3339](https://www.ietf.org/rfc/rfc3339.txt) date strings.
+ *
+ * # Examples
+ *
+ * Example 1: Compute Timestamp from POSIX `time()`.
+ *
+ *     Timestamp timestamp;
+ *     timestamp.set_seconds(time(NULL));
+ *     timestamp.set_nanos(0);
+ *
+ * Example 2: Compute Timestamp from POSIX `gettimeofday()`.
+ *
+ *     struct timeval tv;
+ *     gettimeofday(&tv, NULL);
+ *
+ *     Timestamp timestamp;
+ *     timestamp.set_seconds(tv.tv_sec);
+ *     timestamp.set_nanos(tv.tv_usec * 1000);
+ *
+ * Example 3: Compute Timestamp from Win32 `GetSystemTimeAsFileTime()`.
+ *
+ *     FILETIME ft;
+ *     GetSystemTimeAsFileTime(&ft);
+ *     UINT64 ticks = (((UINT64)ft.dwHighDateTime) << 32) | ft.dwLowDateTime;
+ *
+ *     // A Windows tick is 100 nanoseconds. Windows epoch 1601-01-01T00:00:00Z
+ *     // is 11644473600 seconds before Unix epoch 1970-01-01T00:00:00Z.
+ *     Timestamp timestamp;
+ *     timestamp.set_seconds((INT64) ((ticks / 10000000) - 11644473600LL));
+ *     timestamp.set_nanos((INT32) ((ticks % 10000000) * 100));
+ *
+ * Example 4: Compute Timestamp from Java `System.currentTimeMillis()`.
+ *
+ *     long millis = System.currentTimeMillis();
+ *
+ *     Timestamp timestamp = Timestamp.newBuilder().setSeconds(millis / 1000)
+ *         .setNanos((int) ((millis % 1000) * 1000000)).build();
+ *
+ *
+ * Example 5: Compute Timestamp from Java `Instant.now()`.
+ *
+ *     Instant now = Instant.now();
+ *
+ *     Timestamp timestamp =
+ *         Timestamp.newBuilder().setSeconds(now.getEpochSecond())
+ *             .setNanos(now.getNano()).build();
+ *
+ *
+ * Example 6: Compute Timestamp from current time in Python.
+ *
+ *     timestamp = Timestamp()
+ *     timestamp.GetCurrentTime()
+ *
+ * # JSON Mapping
+ *
+ * In JSON format, the Timestamp type is encoded as a string in the
+ * [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) format. That is, the
+ * format is "{year}-{month}-{day}T{hour}:{min}:{sec}[.{frac_sec}]Z"
+ * where {year} is always expressed using four digits while {month}, {day},
+ * {hour}, {min}, and {sec} are zero-padded to two digits each. The fractional
+ * seconds, which can go up to 9 digits (i.e. up to 1 nanosecond resolution),
+ * are optional. The "Z" suffix indicates the timezone ("UTC"); the timezone
+ * is required. A proto3 JSON serializer should always use UTC (as indicated by
+ * "Z") when printing the Timestamp type and a proto3 JSON parser should be
+ * able to accept both UTC and other timezones (as indicated by an offset).
+ *
+ * For example, "2017-01-15T01:30:15.01Z" encodes 15.01 seconds past
+ * 01:30 UTC on January 15, 2017.
+ *
+ * In JavaScript, one can convert a Date object to this format using the
+ * standard
+ * [toISOString()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString)
+ * method. In Python, a standard `datetime.datetime` object can be converted
+ * to this format using
+ * [`strftime`](https://docs.python.org/2/library/time.html#time.strftime) with
+ * the time format spec '%Y-%m-%dT%H:%M:%S.%fZ'. Likewise, in Java, one can use
+ * the Joda Time's [`ISODateTimeFormat.dateTime()`](
+ * http://www.joda.org/joda-time/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTime%2D%2D
+ * ) to obtain a formatter capable of generating timestamps in this format.
+ */
+export interface Timestamp {
+  /**
+   * Represents seconds of UTC time since Unix epoch
+   * 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
+   * 9999-12-31T23:59:59Z inclusive.
+   */
+  seconds: number;
+  /**
+   * Non-negative fractions of a second at nanosecond resolution. Negative
+   * second values with fractions must still have non-negative nanos values
+   * that count forward in time. Must be from 0 to 999,999,999
+   * inclusive.
+   */
+  nanos: number;
+}
+
+const baseTimestamp: object = { seconds: 0, nanos: 0 };
+
+export const Timestamp = {
+  encode(message: Timestamp, writer: Writer = Writer.create()): Writer {
+    if (message.seconds !== 0) {
+      writer.uint32(8).int64(message.seconds);
+    }
+    if (message.nanos !== 0) {
+      writer.uint32(16).int32(message.nanos);
+    }
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): Timestamp {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseTimestamp } as Timestamp;
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          message.seconds = longToNumber(reader.int64() as Long);
+          break;
+        case 2:
+          message.nanos = reader.int32();
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): Timestamp {
+    const message = { ...baseTimestamp } as Timestamp;
+    message.seconds = object.seconds !== undefined && object.seconds !== null ? Number(object.seconds) : 0;
+    message.nanos = object.nanos !== undefined && object.nanos !== null ? Number(object.nanos) : 0;
+    return message;
+  },
+
+  toJSON(message: Timestamp): unknown {
+    const obj: any = {};
+    message.seconds !== undefined && (obj.seconds = message.seconds);
+    message.nanos !== undefined && (obj.nanos = message.nanos);
+    return obj;
+  },
+
+  fromPartial(object: DeepPartial<Timestamp>): Timestamp {
+    const message = { ...baseTimestamp } as Timestamp;
+    message.seconds = object.seconds ?? 0;
+    message.nanos = object.nanos ?? 0;
+    return message;
+  },
+};
+
+declare var self: any | undefined;
+declare var window: any | undefined;
+declare var global: any | undefined;
+var globalThis: any = (() => {
+  if (typeof globalThis !== 'undefined') return globalThis;
+  if (typeof self !== 'undefined') return self;
+  if (typeof window !== 'undefined') return window;
+  if (typeof global !== 'undefined') return global;
+  throw 'Unable to locate global object';
+})();
+
+type Builtin = Date | Function | Uint8Array | string | number | boolean | undefined;
+export type DeepPartial<T> = T extends Builtin
+  ? T
+  : T extends Array<infer U>
+  ? Array<DeepPartial<U>>
+  : T extends ReadonlyArray<infer U>
+  ? ReadonlyArray<DeepPartial<U>>
+  : T extends {}
+  ? { [K in keyof T]?: DeepPartial<T[K]> }
+  : Partial<T>;
+
+function longToNumber(long: Long): number {
+  if (long.gt(Number.MAX_SAFE_INTEGER)) {
+    throw new globalThis.Error('Value is larger than Number.MAX_SAFE_INTEGER');
+  }
+  return long.toNumber();
+}
+
+// If you get a compile-error about 'Constructor<Long> and ... have no overlap',
+// add '--ts_proto_opt=esModuleInterop=true' as a flag when calling 'protoc'.
+if (util.Long !== Long) {
+  util.Long = Long as any;
+  configure();
+}
diff --git a/integration/simple-json-name/simple-json-name-test.ts b/integration/simple-json-name/simple-json-name-test.ts
new file mode 100644
index 000000000..fe0ddf0dc
--- /dev/null
+++ b/integration/simple-json-name/simple-json-name-test.ts
@@ -0,0 +1,25 @@
+import { Simple } from './simple';
+
+describe('simple', () => {
+  it('generates json field names correctly', () => {
+    const simple: Simple = Simple.fromPartial({ name: 'test' });
+    const convertJsonObject: any = Simple.toJSON(simple);
+    // Check if the generated json field name is correct
+    expect(Object.prototype.hasOwnProperty.call(convertJsonObject, 'other_name')).toBe(true);
+
+    if (typeof convertJsonObject?.other_name === 'string') {
+      expect(convertJsonObject.other_name).toBe('test');
+    }
+
+    // Check if field names from parsed json are correct
+    const jsonObject = {
+      other_name: 'test',
+      other_age: 10,
+      createdAt: '2020-01-01T00:00:00.000Z',
+    };
+    const simple2: Simple = Simple.fromJSON(jsonObject);
+    expect(simple2.name).toBe('test');
+    expect(typeof simple2.age).toBe('number');
+    expect(typeof simple2.createdAt).toBe(typeof new Date());
+  });
+});
diff --git a/integration/simple-json-name/simple.bin b/integration/simple-json-name/simple.bin
new file mode 100644
index 000000000..97d15a687
Binary files /dev/null and b/integration/simple-json-name/simple.bin differ
diff --git a/integration/simple-json-name/simple.proto b/integration/simple-json-name/simple.proto
new file mode 100644
index 000000000..48bf36f0c
--- /dev/null
+++ b/integration/simple-json-name/simple.proto
@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+import "google/protobuf/timestamp.proto";
+
+package simple;
+
+message Simple {
+  string name = 1 [ json_name = "other_name" ];
+  optional int32 age = 2 [ json_name = "other_age" ];
+  optional google.protobuf.Timestamp created_at = 9 [ json_name="createdAt" ];
+}
diff --git a/integration/simple-json-name/simple.ts b/integration/simple-json-name/simple.ts
new file mode 100644
index 000000000..db9761249
--- /dev/null
+++ b/integration/simple-json-name/simple.ts
@@ -0,0 +1,118 @@
+/* eslint-disable */
+import { util, configure, Writer, Reader } from 'protobufjs/minimal';
+import * as Long from 'long';
+import { Timestamp } from './google/protobuf/timestamp';
+
+export const protobufPackage = 'simple';
+
+export interface Simple {
+  name: string;
+  age?: number | undefined;
+  createdAt?: Date | undefined;
+}
+
+const baseSimple: object = { name: '' };
+
+export const Simple = {
+  encode(message: Simple, writer: Writer = Writer.create()): Writer {
+    if (message.name !== '') {
+      writer.uint32(10).string(message.name);
+    }
+    if (message.age !== undefined) {
+      writer.uint32(16).int32(message.age);
+    }
+    if (message.createdAt !== undefined) {
+      Timestamp.encode(toTimestamp(message.createdAt), writer.uint32(74).fork()).ldelim();
+    }
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): Simple {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseSimple } as Simple;
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          message.name = reader.string();
+          break;
+        case 2:
+          message.age = reader.int32();
+          break;
+        case 9:
+          message.createdAt = fromTimestamp(Timestamp.decode(reader, reader.uint32()));
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): Simple {
+    const message = { ...baseSimple } as Simple;
+    message.name = object.other_name !== undefined && object.other_name !== null ? String(object.other_name) : '';
+    message.age = object.other_age !== undefined && object.other_age !== null ? Number(object.other_age) : undefined;
+    message.createdAt =
+      object.createdAt !== undefined && object.createdAt !== null ? fromJsonTimestamp(object.createdAt) : undefined;
+    return message;
+  },
+
+  toJSON(message: Simple): unknown {
+    const obj: any = {};
+    message.name !== undefined && (obj.other_name = message.name);
+    message.age !== undefined && (obj.other_age = message.age);
+    message.createdAt !== undefined && (obj.createdAt = message.createdAt.toISOString());
+    return obj;
+  },
+
+  fromPartial(object: DeepPartial<Simple>): Simple {
+    const message = { ...baseSimple } as Simple;
+    message.name = object.name ?? '';
+    message.age = object.age ?? undefined;
+    message.createdAt = object.createdAt ?? undefined;
+    return message;
+  },
+};
+
+type Builtin = Date | Function | Uint8Array | string | number | boolean | undefined;
+export type DeepPartial<T> = T extends Builtin
+  ? T
+  : T extends Array<infer U>
+  ? Array<DeepPartial<U>>
+  : T extends ReadonlyArray<infer U>
+  ? ReadonlyArray<DeepPartial<U>>
+  : T extends {}
+  ? { [K in keyof T]?: DeepPartial<T[K]> }
+  : Partial<T>;
+
+function toTimestamp(date: Date): Timestamp {
+  const seconds = date.getTime() / 1_000;
+  const nanos = (date.getTime() % 1_000) * 1_000_000;
+  return { seconds, nanos };
+}
+
+function fromTimestamp(t: Timestamp): Date {
+  let millis = t.seconds * 1_000;
+  millis += t.nanos / 1_000_000;
+  return new Date(millis);
+}
+
+function fromJsonTimestamp(o: any): Date {
+  if (o instanceof Date) {
+    return o;
+  } else if (typeof o === 'string') {
+    return new Date(o);
+  } else {
+    return fromTimestamp(Timestamp.fromJSON(o));
+  }
+}
+
+// If you get a compile-error about 'Constructor<Long> and ... have no overlap',
+// add '--ts_proto_opt=esModuleInterop=true' as a flag when calling 'protoc'.
+if (util.Long !== Long) {
+  util.Long = Long as any;
+  configure();
+}
diff --git a/integration/simple-snake/import_dir/thing.ts b/integration/simple-snake/import_dir/thing.ts
index e45e55d4e..3a013304a 100644
--- a/integration/simple-snake/import_dir/thing.ts
+++ b/integration/simple-snake/import_dir/thing.ts
@@ -40,13 +40,13 @@ export const ImportedThing = {
   fromJSON(object: any): ImportedThing {
     const message = { ...baseImportedThing } as ImportedThing;
     message.created_at =
-      object.created_at !== undefined && object.created_at !== null ? fromJsonTimestamp(object.created_at) : undefined;
+      object.createdAt !== undefined && object.createdAt !== null ? fromJsonTimestamp(object.createdAt) : undefined;
     return message;
   },
 
   toJSON(message: ImportedThing): unknown {
     const obj: any = {};
-    message.created_at !== undefined && (obj.created_at = message.created_at.toISOString());
+    message.created_at !== undefined && (obj.createdAt = message.created_at.toISOString());
     return obj;
   },
 
diff --git a/integration/simple-snake/simple.ts b/integration/simple-snake/simple.ts
index 4ce1a42aa..ca2844a71 100644
--- a/integration/simple-snake/simple.ts
+++ b/integration/simple-snake/simple.ts
@@ -344,13 +344,13 @@ export const Simple = {
     message.name = object.name !== undefined && object.name !== null ? String(object.name) : '';
     message.age = object.age !== undefined && object.age !== null ? Number(object.age) : 0;
     message.created_at =
-      object.created_at !== undefined && object.created_at !== null ? fromJsonTimestamp(object.created_at) : undefined;
+      object.createdAt !== undefined && object.createdAt !== null ? fromJsonTimestamp(object.createdAt) : undefined;
     message.child = object.child !== undefined && object.child !== null ? Child.fromJSON(object.child) : undefined;
     message.state = object.state !== undefined && object.state !== null ? stateEnumFromJSON(object.state) : 0;
-    message.grand_children = (object.grand_children ?? []).map((e: any) => Child.fromJSON(e));
+    message.grand_children = (object.grandChildren ?? []).map((e: any) => Child.fromJSON(e));
     message.coins = (object.coins ?? []).map((e: any) => Number(e));
     message.snacks = (object.snacks ?? []).map((e: any) => String(e));
-    message.old_states = (object.old_states ?? []).map((e: any) => stateEnumFromJSON(e));
+    message.old_states = (object.oldStates ?? []).map((e: any) => stateEnumFromJSON(e));
     message.thing =
       object.thing !== undefined && object.thing !== null ? ImportedThing.fromJSON(object.thing) : undefined;
     return message;
@@ -360,13 +360,13 @@ export const Simple = {
     const obj: any = {};
     message.name !== undefined && (obj.name = message.name);
     message.age !== undefined && (obj.age = message.age);
-    message.created_at !== undefined && (obj.created_at = message.created_at.toISOString());
+    message.created_at !== undefined && (obj.createdAt = message.created_at.toISOString());
     message.child !== undefined && (obj.child = message.child ? Child.toJSON(message.child) : undefined);
     message.state !== undefined && (obj.state = stateEnumToJSON(message.state));
     if (message.grand_children) {
-      obj.grand_children = message.grand_children.map((e) => (e ? Child.toJSON(e) : undefined));
+      obj.grandChildren = message.grand_children.map((e) => (e ? Child.toJSON(e) : undefined));
     } else {
-      obj.grand_children = [];
+      obj.grandChildren = [];
     }
     if (message.coins) {
       obj.coins = message.coins.map((e) => e);
@@ -379,9 +379,9 @@ export const Simple = {
       obj.snacks = [];
     }
     if (message.old_states) {
-      obj.old_states = message.old_states.map((e) => stateEnumToJSON(e));
+      obj.oldStates = message.old_states.map((e) => stateEnumToJSON(e));
     } else {
-      obj.old_states = [];
+      obj.oldStates = [];
     }
     message.thing !== undefined && (obj.thing = message.thing ? ImportedThing.toJSON(message.thing) : undefined);
     return obj;
@@ -1174,7 +1174,7 @@ export const SimpleWithSnakeCaseMap = {
 
   fromJSON(object: any): SimpleWithSnakeCaseMap {
     const message = { ...baseSimpleWithSnakeCaseMap } as SimpleWithSnakeCaseMap;
-    message.entities_by_id = Object.entries(object.entities_by_id ?? {}).reduce<{ [key: number]: Entity }>(
+    message.entities_by_id = Object.entries(object.entitiesById ?? {}).reduce<{ [key: number]: Entity }>(
       (acc, [key, value]) => {
         acc[Number(key)] = Entity.fromJSON(value);
         return acc;
@@ -1186,10 +1186,10 @@ export const SimpleWithSnakeCaseMap = {
 
   toJSON(message: SimpleWithSnakeCaseMap): unknown {
     const obj: any = {};
-    obj.entities_by_id = {};
+    obj.entitiesById = {};
     if (message.entities_by_id) {
       Object.entries(message.entities_by_id).forEach(([k, v]) => {
-        obj.entities_by_id[k] = Entity.toJSON(v);
+        obj.entitiesById[k] = Entity.toJSON(v);
       });
     }
     return obj;
diff --git a/src/main.ts b/src/main.ts
index e9f196a9e..25bb44d7c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -38,7 +38,13 @@ import {
   isStructType,
 } from './types';
 import SourceInfo, { Fields } from './sourceInfo';
-import { assertInstanceOf, FormattedMethodDescriptor, maybeAddComment, maybePrefixPackage } from './utils';
+import {
+  assertInstanceOf,
+  determineFieldJsonName,
+  FormattedMethodDescriptor,
+  maybeAddComment,
+  maybePrefixPackage,
+} from './utils';
 import { camelToSnake, capitalize, maybeSnakeToCamel } from './case';
 import {
   generateNestjsGrpcServiceMethodsDecorator,
@@ -994,6 +1000,7 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
   // add a check for each incoming field
   messageDesc.field.forEach((field) => {
     const fieldName = maybeSnakeToCamel(field.name, options);
+    const jsonName = determineFieldJsonName(field, options);
 
     // get a generic 'reader.doSomething' bit that is specific to the basic type
     const readSnippet = (from: string): Code => {
@@ -1085,26 +1092,26 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
         const fieldType = toTypeName(ctx, messageDesc, field);
         const i = maybeCastToNumber(ctx, messageDesc, field, 'key');
         chunks.push(code`
-          message.${fieldName} = Object.entries(object.${fieldName} ?? {}).reduce<${fieldType}>((acc, [key, value]) => {
+          message.${fieldName} = Object.entries(object.${jsonName} ?? {}).reduce<${fieldType}>((acc, [key, value]) => {
             acc[${i}] = ${readSnippet('value')};
             return acc;
           }, {});
         `);
       } else if (isAnyValueType(field)) {
         chunks.push(code`
-          message.${fieldName} = Array.isArray(object?.${fieldName}) ? [...object.${fieldName}] : [];
+          message.${fieldName} = Array.isArray(object?.${jsonName}) ? [...object.${jsonName}] : [];
         `);
       } else {
         // Explicit `any` type required to make TS with noImplicitAny happy. `object` is also `any` here.
         chunks.push(code`
-          message.${fieldName} = (object.${fieldName} ?? []).map((e: any) => ${readSnippet('e')});
+          message.${fieldName} = (object.${jsonName} ?? []).map((e: any) => ${readSnippet('e')});
         `);
       }
     } else if (isWithinOneOfThatShouldBeUnion(options, field)) {
-      chunks.push(code`if (object.${fieldName} !== undefined && object.${fieldName} !== null) {`);
+      chunks.push(code`if (object.${jsonName} !== undefined && object.${jsonName} !== null) {`);
       const oneofName = maybeSnakeToCamel(messageDesc.oneofDecl[field.oneofIndex].name, options);
       chunks.push(code`
-        message.${oneofName} = { $case: '${fieldName}', ${fieldName}: ${readSnippet(`object.${fieldName}`)} }
+        message.${oneofName} = { $case: '${fieldName}', ${fieldName}: ${readSnippet(`object.${jsonName}`)} }
       `);
       chunks.push(code`}`);
     } else if (isAnyValueType(field)) {
@@ -1122,8 +1129,8 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
     } else {
       const fallback = isWithinOneOf(field) ? 'undefined' : defaultValue(ctx, field);
       chunks.push(code`
-        message.${fieldName} = (object.${fieldName} !== undefined && object.${fieldName} !== null)
-          ? ${readSnippet(`object.${fieldName}`)}
+        message.${fieldName} = (object.${jsonName} !== undefined && object.${jsonName} !== null)
+          ? ${readSnippet(`object.${jsonName}`)}
           : ${fallback};
       `);
     }
@@ -1147,6 +1154,7 @@ function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorP
   // then add a case for each field
   messageDesc.field.forEach((field) => {
     const fieldName = maybeSnakeToCamel(field.name, options);
+    const jsonName = determineFieldJsonName(field, options);
 
     const readSnippet = (from: string): Code => {
       if (isEnum(field)) {
@@ -1206,10 +1214,10 @@ function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorP
     if (isMapType(ctx, messageDesc, field)) {
       // Maps might need their values transformed, i.e. bytes --> base64
       chunks.push(code`
-        obj.${fieldName} = {};
+        obj.${jsonName} = {};
         if (message.${fieldName}) {
           Object.entries(message.${fieldName}).forEach(([k, v]) => {
-            obj.${fieldName}[k] = ${readSnippet('v')};
+            obj.${jsonName}[k] = ${readSnippet('v')};
           });
         }
       `);
@@ -1217,19 +1225,19 @@ function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorP
       // Arrays might need their elements transformed
       chunks.push(code`
         if (message.${fieldName}) {
-          obj.${fieldName} = message.${fieldName}.map(e => ${readSnippet('e')});
+          obj.${jsonName} = message.${fieldName}.map(e => ${readSnippet('e')});
         } else {
-          obj.${fieldName} = [];
+          obj.${jsonName} = [];
         }
       `);
     } else if (isWithinOneOfThatShouldBeUnion(options, field)) {
       // oneofs in a union are only output as `oneof name = ...`
       const oneofName = maybeSnakeToCamel(messageDesc.oneofDecl[field.oneofIndex].name, options);
       const v = readSnippet(`message.${oneofName}?.${fieldName}`);
-      chunks.push(code`message.${oneofName}?.$case === '${fieldName}' && (obj.${fieldName} = ${v});`);
+      chunks.push(code`message.${oneofName}?.$case === '${fieldName}' && (obj.${jsonName} = ${v});`);
     } else {
       const v = readSnippet(`message.${fieldName}`);
-      chunks.push(code`message.${fieldName} !== undefined && (obj.${fieldName} = ${v});`);
+      chunks.push(code`message.${fieldName} !== undefined && (obj.${jsonName} = ${v});`);
     }
   });
   chunks.push(code`return obj;`);
diff --git a/src/utils.ts b/src/utils.ts
index 5b3f8c669..f4fdfb993 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,9 +1,15 @@
 import { code, Code } from 'ts-poet';
-import { CodeGeneratorRequest, FileDescriptorProto, MethodDescriptorProto, MethodOptions } from 'ts-proto-descriptors';
+import {
+  CodeGeneratorRequest,
+  FieldDescriptorProto,
+  FileDescriptorProto,
+  MethodDescriptorProto,
+  MethodOptions,
+} from 'ts-proto-descriptors';
 import ReadStream = NodeJS.ReadStream;
 import { SourceDescription } from './sourceInfo';
 import { Options, ServiceOption } from './options';
-import { camelCase } from './case';
+import { camelCase, maybeSnakeToCamel } from './case';
 
 export function protoFilesToGenerate(request: CodeGeneratorRequest): FileDescriptorProto[] {
   return request.protoFile.filter((f) => request.fileToGenerate.includes(f.name));
@@ -167,3 +173,12 @@ export class FormattedMethodDescriptor implements MethodDescriptorProto {
     return result;
   }
 }
+
+export function determineFieldJsonName(field: FieldDescriptorProto, options: Options): string {
+  // By default jsonName is camelCased by the protocol compilier unless the user has
+  // set a "json_name" option on this field.
+  if (field.jsonName.length > 0) {
+    return field.jsonName;
+  }
+  return maybeSnakeToCamel(field.name, options);
+}