diff --git a/pgtype/json.go b/pgtype/json.go
index 3f1a750f6..99628092a 100644
--- a/pgtype/json.go
+++ b/pgtype/json.go
@@ -25,6 +25,11 @@ func (c JSONCodec) PlanEncode(m *Map, oid uint32, format int16, value any) Encod
 	case []byte:
 		return encodePlanJSONCodecEitherFormatByteSlice{}
 
+	// Handle json.RawMessage specifically because if it is run through json.Marshal it may be mutated.
+	// e.g. `{"foo": "bar"}` -> `{"foo":"bar"}`.
+	case json.RawMessage:
+		return encodePlanJSONCodecEitherFormatJSONRawMessage{}
+
 	// Cannot rely on driver.Valuer being handled later because anything can be marshalled.
 	//
 	// https://github.com/jackc/pgx/issues/1430
@@ -79,6 +84,18 @@ func (encodePlanJSONCodecEitherFormatByteSlice) Encode(value any, buf []byte) (n
 	return buf, nil
 }
 
+type encodePlanJSONCodecEitherFormatJSONRawMessage struct{}
+
+func (encodePlanJSONCodecEitherFormatJSONRawMessage) Encode(value any, buf []byte) (newBuf []byte, err error) {
+	jsonBytes := value.(json.RawMessage)
+	if jsonBytes == nil {
+		return nil, nil
+	}
+
+	buf = append(buf, jsonBytes...)
+	return buf, nil
+}
+
 type encodePlanJSONCodecEitherFormatMarshal struct{}
 
 func (encodePlanJSONCodecEitherFormatMarshal) Encode(value any, buf []byte) (newBuf []byte, err error) {
diff --git a/pgtype/pgtype_default.go b/pgtype/pgtype_default.go
index 58f4b92c7..c21ac081e 100644
--- a/pgtype/pgtype_default.go
+++ b/pgtype/pgtype_default.go
@@ -1,6 +1,7 @@
 package pgtype
 
 import (
+	"encoding/json"
 	"net"
 	"net/netip"
 	"reflect"
@@ -173,6 +174,7 @@ func initDefaultMap() {
 	registerDefaultPgTypeVariants[time.Time](defaultMap, "timestamptz")
 	registerDefaultPgTypeVariants[time.Duration](defaultMap, "interval")
 	registerDefaultPgTypeVariants[string](defaultMap, "text")
+	registerDefaultPgTypeVariants[json.RawMessage](defaultMap, "json")
 	registerDefaultPgTypeVariants[[]byte](defaultMap, "bytea")
 
 	registerDefaultPgTypeVariants[net.IP](defaultMap, "inet")
diff --git a/pgtype/pgtype_test.go b/pgtype/pgtype_test.go
index c397069b1..b670e92b8 100644
--- a/pgtype/pgtype_test.go
+++ b/pgtype/pgtype_test.go
@@ -546,6 +546,14 @@ func TestMapEncodePlanCacheUUIDTypeConfusion(t *testing.T) {
 	require.Error(t, err)
 }
 
+// https://github.com/jackc/pgx/issues/1763
+func TestMapEncodeRawJSONIntoUnknownOID(t *testing.T) {
+	m := pgtype.NewMap()
+	buf, err := m.Encode(0, pgtype.TextFormatCode, json.RawMessage(`{"foo": "bar"}`), nil)
+	require.NoError(t, err)
+	require.Equal(t, []byte(`{"foo": "bar"}`), buf)
+}
+
 func BenchmarkMapScanInt4IntoBinaryDecoder(b *testing.B) {
 	m := pgtype.NewMap()
 	src := []byte{0, 0, 0, 42}