diff --git a/integration/grpc-js/google/protobuf/struct.ts b/integration/grpc-js/google/protobuf/struct.ts
index 28fe05424..b89d50460 100644
--- a/integration/grpc-js/google/protobuf/struct.ts
+++ b/integration/grpc-js/google/protobuf/struct.ts
@@ -334,7 +334,7 @@ export const Value = {
 
   wrap(value: any): Value {
     if (value === null) {
-      return { nullValue: 0 } as Value;
+      return { nullValue: NullValue.NULL_VALUE } as Value;
     } else if (typeof value === 'boolean') {
       return { boolValue: value } as Value;
     } else if (typeof value === 'number') {
diff --git a/integration/simple-string-enums/google/protobuf/struct.ts b/integration/simple-string-enums/google/protobuf/struct.ts
new file mode 100644
index 000000000..d1d4d5154
--- /dev/null
+++ b/integration/simple-string-enums/google/protobuf/struct.ts
@@ -0,0 +1,463 @@
+/* eslint-disable */
+import { util, configure, Writer, Reader } from 'protobufjs/minimal';
+import * as Long from 'long';
+
+export const protobufPackage = 'google.protobuf';
+
+/**
+ * `NullValue` is a singleton enumeration to represent the null value for the
+ * `Value` type union.
+ *
+ *  The JSON representation for `NullValue` is JSON `null`.
+ */
+export enum NullValue {
+  /** NULL_VALUE - Null value. */
+  NULL_VALUE = 'NULL_VALUE',
+  UNRECOGNIZED = 'UNRECOGNIZED',
+}
+
+export function nullValueFromJSON(object: any): NullValue {
+  switch (object) {
+    case 0:
+    case 'NULL_VALUE':
+      return NullValue.NULL_VALUE;
+    case -1:
+    case 'UNRECOGNIZED':
+    default:
+      return NullValue.UNRECOGNIZED;
+  }
+}
+
+export function nullValueToJSON(object: NullValue): string {
+  switch (object) {
+    case NullValue.NULL_VALUE:
+      return 'NULL_VALUE';
+    default:
+      return 'UNKNOWN';
+  }
+}
+
+export function nullValueToNumber(object: NullValue): number {
+  switch (object) {
+    case NullValue.NULL_VALUE:
+      return 0;
+    default:
+      return 0;
+  }
+}
+
+/**
+ * `Struct` represents a structured data value, consisting of fields
+ * which map to dynamically typed values. In some languages, `Struct`
+ * might be supported by a native representation. For example, in
+ * scripting languages like JS a struct is represented as an
+ * object. The details of that representation are described together
+ * with the proto support for the language.
+ *
+ * The JSON representation for `Struct` is JSON object.
+ */
+export interface Struct {
+  /** Unordered map of dynamically typed values. */
+  fields: { [key: string]: any | undefined };
+}
+
+export interface Struct_FieldsEntry {
+  key: string;
+  value: any | undefined;
+}
+
+/**
+ * `Value` represents a dynamically typed value which can be either
+ * null, a number, a string, a boolean, a recursive struct value, or a
+ * list of values. A producer of value is expected to set one of these
+ * variants. Absence of any variant indicates an error.
+ *
+ * The JSON representation for `Value` is JSON value.
+ */
+export interface Value {
+  /** Represents a null value. */
+  nullValue: NullValue | undefined;
+  /** Represents a double value. */
+  numberValue: number | undefined;
+  /** Represents a string value. */
+  stringValue: string | undefined;
+  /** Represents a boolean value. */
+  boolValue: boolean | undefined;
+  /** Represents a structured value. */
+  structValue: { [key: string]: any } | undefined;
+  /** Represents a repeated `Value`. */
+  listValue: Array<any> | undefined;
+}
+
+/**
+ * `ListValue` is a wrapper around a repeated field of values.
+ *
+ * The JSON representation for `ListValue` is JSON array.
+ */
+export interface ListValue {
+  /** Repeated field of dynamically typed values. */
+  values: any[];
+}
+
+const baseStruct: object = {};
+
+export const Struct = {
+  encode(message: Struct, writer: Writer = Writer.create()): Writer {
+    Object.entries(message.fields).forEach(([key, value]) => {
+      if (value !== undefined) {
+        Struct_FieldsEntry.encode({ key: key as any, value }, writer.uint32(10).fork()).ldelim();
+      }
+    });
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): Struct {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseStruct } as Struct;
+    message.fields = {};
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          const entry1 = Struct_FieldsEntry.decode(reader, reader.uint32());
+          if (entry1.value !== undefined) {
+            message.fields[entry1.key] = entry1.value;
+          }
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): Struct {
+    const message = { ...baseStruct } as Struct;
+    message.fields = Object.entries(object.fields ?? {}).reduce<{ [key: string]: any | undefined }>(
+      (acc, [key, value]) => {
+        acc[key] = value as any | undefined;
+        return acc;
+      },
+      {}
+    );
+    return message;
+  },
+
+  toJSON(message: Struct): unknown {
+    const obj: any = {};
+    obj.fields = {};
+    if (message.fields) {
+      Object.entries(message.fields).forEach(([k, v]) => {
+        obj.fields[k] = v;
+      });
+    }
+    return obj;
+  },
+
+  fromPartial<I extends Exact<DeepPartial<Struct>, I>>(object: I): Struct {
+    const message = { ...baseStruct } as Struct;
+    message.fields = Object.entries(object.fields ?? {}).reduce<{ [key: string]: any | undefined }>(
+      (acc, [key, value]) => {
+        if (value !== undefined) {
+          acc[key] = value;
+        }
+        return acc;
+      },
+      {}
+    );
+    return message;
+  },
+
+  wrap(object: { [key: string]: any } | undefined): Struct {
+    const struct = Struct.fromPartial({});
+    if (object !== undefined) {
+      Object.keys(object).forEach((key) => {
+        struct.fields[key] = object[key];
+      });
+    }
+    return struct;
+  },
+
+  unwrap(message: Struct): { [key: string]: any } {
+    const object: { [key: string]: any } = {};
+    Object.keys(message.fields).forEach((key) => {
+      object[key] = message.fields[key];
+    });
+    return object;
+  },
+};
+
+const baseStruct_FieldsEntry: object = { key: '' };
+
+export const Struct_FieldsEntry = {
+  encode(message: Struct_FieldsEntry, writer: Writer = Writer.create()): Writer {
+    if (message.key !== '') {
+      writer.uint32(10).string(message.key);
+    }
+    if (message.value !== undefined) {
+      Value.encode(Value.wrap(message.value), writer.uint32(18).fork()).ldelim();
+    }
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): Struct_FieldsEntry {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseStruct_FieldsEntry } as Struct_FieldsEntry;
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          message.key = reader.string();
+          break;
+        case 2:
+          message.value = Value.unwrap(Value.decode(reader, reader.uint32()));
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): Struct_FieldsEntry {
+    const message = { ...baseStruct_FieldsEntry } as Struct_FieldsEntry;
+    message.key = object.key !== undefined && object.key !== null ? String(object.key) : '';
+    message.value = object.value;
+    return message;
+  },
+
+  toJSON(message: Struct_FieldsEntry): unknown {
+    const obj: any = {};
+    message.key !== undefined && (obj.key = message.key);
+    message.value !== undefined && (obj.value = message.value);
+    return obj;
+  },
+
+  fromPartial<I extends Exact<DeepPartial<Struct_FieldsEntry>, I>>(object: I): Struct_FieldsEntry {
+    const message = { ...baseStruct_FieldsEntry } as Struct_FieldsEntry;
+    message.key = object.key ?? '';
+    message.value = object.value ?? undefined;
+    return message;
+  },
+};
+
+const baseValue: object = {};
+
+export const Value = {
+  encode(message: Value, writer: Writer = Writer.create()): Writer {
+    if (message.nullValue !== undefined) {
+      writer.uint32(8).int32(nullValueToNumber(message.nullValue));
+    }
+    if (message.numberValue !== undefined) {
+      writer.uint32(17).double(message.numberValue);
+    }
+    if (message.stringValue !== undefined) {
+      writer.uint32(26).string(message.stringValue);
+    }
+    if (message.boolValue !== undefined) {
+      writer.uint32(32).bool(message.boolValue);
+    }
+    if (message.structValue !== undefined) {
+      Struct.encode(Struct.wrap(message.structValue), writer.uint32(42).fork()).ldelim();
+    }
+    if (message.listValue !== undefined) {
+      ListValue.encode(ListValue.wrap(message.listValue), writer.uint32(50).fork()).ldelim();
+    }
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): Value {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseValue } as Value;
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          message.nullValue = nullValueFromJSON(reader.int32());
+          break;
+        case 2:
+          message.numberValue = reader.double();
+          break;
+        case 3:
+          message.stringValue = reader.string();
+          break;
+        case 4:
+          message.boolValue = reader.bool();
+          break;
+        case 5:
+          message.structValue = Struct.unwrap(Struct.decode(reader, reader.uint32()));
+          break;
+        case 6:
+          message.listValue = ListValue.unwrap(ListValue.decode(reader, reader.uint32()));
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): Value {
+    const message = { ...baseValue } as Value;
+    message.nullValue =
+      object.nullValue !== undefined && object.nullValue !== null ? nullValueFromJSON(object.nullValue) : undefined;
+    message.numberValue =
+      object.numberValue !== undefined && object.numberValue !== null ? Number(object.numberValue) : undefined;
+    message.stringValue =
+      object.stringValue !== undefined && object.stringValue !== null ? String(object.stringValue) : undefined;
+    message.boolValue =
+      object.boolValue !== undefined && object.boolValue !== null ? Boolean(object.boolValue) : undefined;
+    message.structValue = typeof object.structValue === 'object' ? object.structValue : undefined;
+    message.listValue = Array.isArray(object?.listValue) ? [...object.listValue] : undefined;
+    return message;
+  },
+
+  toJSON(message: Value): unknown {
+    const obj: any = {};
+    message.nullValue !== undefined &&
+      (obj.nullValue = message.nullValue !== undefined ? nullValueToJSON(message.nullValue) : undefined);
+    message.numberValue !== undefined && (obj.numberValue = message.numberValue);
+    message.stringValue !== undefined && (obj.stringValue = message.stringValue);
+    message.boolValue !== undefined && (obj.boolValue = message.boolValue);
+    message.structValue !== undefined && (obj.structValue = message.structValue);
+    message.listValue !== undefined && (obj.listValue = message.listValue);
+    return obj;
+  },
+
+  fromPartial<I extends Exact<DeepPartial<Value>, I>>(object: I): Value {
+    const message = { ...baseValue } as Value;
+    message.nullValue = object.nullValue ?? undefined;
+    message.numberValue = object.numberValue ?? undefined;
+    message.stringValue = object.stringValue ?? undefined;
+    message.boolValue = object.boolValue ?? undefined;
+    message.structValue = object.structValue ?? undefined;
+    message.listValue = object.listValue ?? undefined;
+    return message;
+  },
+
+  wrap(value: any): Value {
+    if (value === null) {
+      return { nullValue: NullValue.NULL_VALUE } as Value;
+    } else if (typeof value === 'boolean') {
+      return { boolValue: value } as Value;
+    } else if (typeof value === 'number') {
+      return { numberValue: value } as Value;
+    } else if (typeof value === 'string') {
+      return { stringValue: value } as Value;
+    } else if (Array.isArray(value)) {
+      return { listValue: value } as Value;
+    } else if (typeof value === 'object') {
+      return { structValue: value } as Value;
+    } else if (typeof value === 'undefined') {
+      return {} as Value;
+    } else {
+      throw new Error('Unsupported any value type: ' + typeof value);
+    }
+  },
+
+  unwrap(message: Value): string | number | boolean | Object | null | Array<any> | undefined {
+    if (message.stringValue !== undefined) {
+      return message.stringValue;
+    } else if (message.numberValue !== undefined) {
+      return message.numberValue;
+    } else if (message.boolValue !== undefined) {
+      return message.boolValue;
+    } else if (message.structValue !== undefined) {
+      return message.structValue;
+    } else if (message.listValue !== undefined) {
+      return message.listValue;
+    } else if (message.nullValue !== undefined) {
+      return null;
+    }
+  },
+};
+
+const baseListValue: object = {};
+
+export const ListValue = {
+  encode(message: ListValue, writer: Writer = Writer.create()): Writer {
+    for (const v of message.values) {
+      Value.encode(Value.wrap(v!), writer.uint32(10).fork()).ldelim();
+    }
+    return writer;
+  },
+
+  decode(input: Reader | Uint8Array, length?: number): ListValue {
+    const reader = input instanceof Reader ? input : new Reader(input);
+    let end = length === undefined ? reader.len : reader.pos + length;
+    const message = { ...baseListValue } as ListValue;
+    message.values = [];
+    while (reader.pos < end) {
+      const tag = reader.uint32();
+      switch (tag >>> 3) {
+        case 1:
+          message.values.push(Value.unwrap(Value.decode(reader, reader.uint32())));
+          break;
+        default:
+          reader.skipType(tag & 7);
+          break;
+      }
+    }
+    return message;
+  },
+
+  fromJSON(object: any): ListValue {
+    const message = { ...baseListValue } as ListValue;
+    message.values = Array.isArray(object?.values) ? [...object.values] : [];
+    return message;
+  },
+
+  toJSON(message: ListValue): unknown {
+    const obj: any = {};
+    if (message.values) {
+      obj.values = message.values.map((e) => e);
+    } else {
+      obj.values = [];
+    }
+    return obj;
+  },
+
+  fromPartial<I extends Exact<DeepPartial<ListValue>, I>>(object: I): ListValue {
+    const message = { ...baseListValue } as ListValue;
+    message.values = object.values?.map((e) => e) || [];
+    return message;
+  },
+
+  wrap(value: Array<any>): ListValue {
+    return { values: value };
+  },
+
+  unwrap(message: ListValue): Array<any> {
+    return message.values;
+  },
+};
+
+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>;
+
+type KeysOfUnion<T> = T extends T ? keyof T : never;
+export type Exact<P, I extends P> = P extends Builtin
+  ? P
+  : P & { [K in keyof P]: Exact<P[K], I[K]> } & Record<Exclude<keyof I, KeysOfUnion<P>>, never>;
+
+// 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-string-enums/simple-test.ts b/integration/simple-string-enums/simple-test.ts
index 5d8afda9c..978f49317 100644
--- a/integration/simple-string-enums/simple-test.ts
+++ b/integration/simple-string-enums/simple-test.ts
@@ -1,13 +1,15 @@
 import { Simple, StateEnum } from './simple';
+import { NullValue } from "./google/protobuf/struct";
 
 describe('simple-string-enums', () => {
   it('encodes', () => {
-    const s1: Simple = { name: 'a', state: StateEnum.ON, states: [StateEnum.ON, StateEnum.OFF] };
+    const s1: Simple = { name: 'a', state: StateEnum.ON, states: [StateEnum.ON, StateEnum.OFF], nullValue: NullValue.NULL_VALUE };
     const b = Simple.encode(s1).finish();
     const s2 = Simple.decode(b);
     expect(s2).toMatchInlineSnapshot(`
       Object {
         "name": "a",
+        "nullValue": "NULL_VALUE",
         "state": "ON",
         "states": Array [
           "ON",
diff --git a/integration/simple-string-enums/simple.bin b/integration/simple-string-enums/simple.bin
index 8729b3131..d19b05e80 100644
Binary files a/integration/simple-string-enums/simple.bin and b/integration/simple-string-enums/simple.bin differ
diff --git a/integration/simple-string-enums/simple.proto b/integration/simple-string-enums/simple.proto
index d1d0e2665..ccf132a83 100644
--- a/integration/simple-string-enums/simple.proto
+++ b/integration/simple-string-enums/simple.proto
@@ -1,10 +1,12 @@
 syntax = "proto3";
 package simple;
+import "google/protobuf/struct.proto";
 
 message Simple {
   string name = 1;
   StateEnum state = 4;
   repeated StateEnum states = 5;
+  google.protobuf.NullValue nullValue = 6;
 }
 
 enum StateEnum {
diff --git a/integration/simple-string-enums/simple.ts b/integration/simple-string-enums/simple.ts
index 41b0b1ee3..2aeaedaf5 100644
--- a/integration/simple-string-enums/simple.ts
+++ b/integration/simple-string-enums/simple.ts
@@ -1,6 +1,7 @@
 /* eslint-disable */
 import { util, configure, Writer, Reader } from 'protobufjs/minimal';
 import * as Long from 'long';
+import { NullValue, nullValueToNumber, nullValueFromJSON, nullValueToJSON } from './google/protobuf/struct';
 
 export const protobufPackage = 'simple';
 
@@ -59,9 +60,15 @@ export interface Simple {
   name: string;
   state: StateEnum;
   states: StateEnum[];
+  nullValue: NullValue;
 }
 
-const baseSimple: object = { name: '', state: StateEnum.UNKNOWN, states: StateEnum.UNKNOWN };
+const baseSimple: object = {
+  name: '',
+  state: StateEnum.UNKNOWN,
+  states: StateEnum.UNKNOWN,
+  nullValue: NullValue.NULL_VALUE,
+};
 
 export const Simple = {
   encode(message: Simple, writer: Writer = Writer.create()): Writer {
@@ -76,6 +83,9 @@ export const Simple = {
       writer.int32(stateEnumToNumber(v));
     }
     writer.ldelim();
+    if (message.nullValue !== NullValue.NULL_VALUE) {
+      writer.uint32(48).int32(nullValueToNumber(message.nullValue));
+    }
     return writer;
   },
 
@@ -103,6 +113,9 @@ export const Simple = {
             message.states.push(stateEnumFromJSON(reader.int32()));
           }
           break;
+        case 6:
+          message.nullValue = nullValueFromJSON(reader.int32());
+          break;
         default:
           reader.skipType(tag & 7);
           break;
@@ -117,6 +130,10 @@ export const Simple = {
     message.state =
       object.state !== undefined && object.state !== null ? stateEnumFromJSON(object.state) : StateEnum.UNKNOWN;
     message.states = (object.states ?? []).map((e: any) => stateEnumFromJSON(e));
+    message.nullValue =
+      object.nullValue !== undefined && object.nullValue !== null
+        ? nullValueFromJSON(object.nullValue)
+        : NullValue.NULL_VALUE;
     return message;
   },
 
@@ -129,6 +146,7 @@ export const Simple = {
     } else {
       obj.states = [];
     }
+    message.nullValue !== undefined && (obj.nullValue = nullValueToJSON(message.nullValue));
     return obj;
   },
 
@@ -137,6 +155,7 @@ export const Simple = {
     message.name = object.name ?? '';
     message.state = object.state ?? StateEnum.UNKNOWN;
     message.states = object.states?.map((e) => e) || [];
+    message.nullValue = object.nullValue ?? NullValue.NULL_VALUE;
     return message;
   },
 };
diff --git a/integration/struct/google/protobuf/struct.ts b/integration/struct/google/protobuf/struct.ts
index 28fe05424..b89d50460 100644
--- a/integration/struct/google/protobuf/struct.ts
+++ b/integration/struct/google/protobuf/struct.ts
@@ -334,7 +334,7 @@ export const Value = {
 
   wrap(value: any): Value {
     if (value === null) {
-      return { nullValue: 0 } as Value;
+      return { nullValue: NullValue.NULL_VALUE } as Value;
     } else if (typeof value === 'boolean') {
       return { boolValue: value } as Value;
     } else if (typeof value === 'number') {
diff --git a/integration/value/google/protobuf/struct.ts b/integration/value/google/protobuf/struct.ts
index 28fe05424..b89d50460 100644
--- a/integration/value/google/protobuf/struct.ts
+++ b/integration/value/google/protobuf/struct.ts
@@ -334,7 +334,7 @@ export const Value = {
 
   wrap(value: any): Value {
     if (value === null) {
-      return { nullValue: 0 } as Value;
+      return { nullValue: NullValue.NULL_VALUE } as Value;
     } else if (typeof value === 'boolean') {
       return { boolValue: value } as Value;
     } else if (typeof value === 'number') {
diff --git a/src/main.ts b/src/main.ts
index 0f1fa60d3..9e39cfa44 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1328,7 +1328,7 @@ function generateWrap(fullProtoTypeName: string): Code[] {
   if (isAnyValueTypeName(fullProtoTypeName)) {
     chunks.push(code`wrap(value: any): Value {
       if (value === null) {
-        return {nullValue: 0} as Value;
+        return {nullValue: NullValue.NULL_VALUE} as Value;
       } else if (typeof value === 'boolean') {
         return {boolValue: value} as Value;
       } else if (typeof value === 'number') {