diff --git a/cmd/protoc-gen-openapi/README.md b/cmd/protoc-gen-openapi/README.md
index 80efa37b..20b16922 100644
--- a/cmd/protoc-gen-openapi/README.md
+++ b/cmd/protoc-gen-openapi/README.md
@@ -63,3 +63,17 @@ refers to additional .proto files in the same directory as
               schema:
                 $ref: '#/components/schemas/google.rpc.Status'
       ```
+9. `int64_as_string`: use string for 64-bit integer serialization.
+   Using "false" generates a scheme incompatible with official proto JSON serialization, but maybe more accurately represent the types used in some cases.
+   - **default**: true
+   - `false`: output all 64-bit integer fields as type `integer` and the specific type under format
+      ```yaml
+      schema:
+        type: integer
+        format: int64
+      ```
+   - `true`: setting type to `string`
+      ```yaml
+      schema:
+        type: string
+      ```
diff --git a/cmd/protoc-gen-openapi/generator/generator.go b/cmd/protoc-gen-openapi/generator/generator.go
index 1c79f970..5211a1fb 100644
--- a/cmd/protoc-gen-openapi/generator/generator.go
+++ b/cmd/protoc-gen-openapi/generator/generator.go
@@ -44,6 +44,7 @@ type Configuration struct {
 	CircularDepth   *int
 	DefaultResponse *bool
 	OutputMode      *string
+	Int64AsString   *bool
 }
 
 const (
diff --git a/cmd/protoc-gen-openapi/generator/reflector.go b/cmd/protoc-gen-openapi/generator/reflector.go
index 31a0f930..b210c7d9 100644
--- a/cmd/protoc-gen-openapi/generator/reflector.go
+++ b/cmd/protoc-gen-openapi/generator/reflector.go
@@ -163,7 +163,14 @@ func (r *OpenAPIv3Reflector) schemaOrReferenceForMessage(message protoreflect.Me
 	case ".google.protobuf.Int32Value", ".google.protobuf.UInt32Value":
 		return wk.NewIntegerSchema(getValueKind(message))
 
-	case ".google.protobuf.StringValue", ".google.protobuf.Int64Value", ".google.protobuf.UInt64Value":
+	case ".google.protobuf.Int64Value", ".google.protobuf.UInt64Value":
+		if *r.conf.Int64AsString {
+			return wk.NewStringSchema()
+		} else {
+			return wk.NewIntegerSchema(getValueKind(message))
+		}
+
+	case ".google.protobuf.StringValue":
 		return wk.NewStringSchema()
 
 	case ".google.protobuf.FloatValue", ".google.protobuf.DoubleValue":
@@ -213,7 +220,11 @@ func (r *OpenAPIv3Reflector) schemaOrReferenceForField(field protoreflect.FieldD
 
 	case protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Uint64Kind,
 		protoreflect.Sfixed64Kind, protoreflect.Fixed64Kind:
-		kindSchema = wk.NewStringSchema()
+		if *r.conf.Int64AsString {
+			kindSchema = wk.NewStringSchema()
+		} else {
+			kindSchema = wk.NewIntegerSchema(kind.String())
+		}
 
 	case protoreflect.EnumKind:
 		kindSchema = wk.NewEnumSchema(*&r.conf.EnumType, field)
diff --git a/cmd/protoc-gen-openapi/main.go b/cmd/protoc-gen-openapi/main.go
index 75405aed..c553b5d5 100644
--- a/cmd/protoc-gen-openapi/main.go
+++ b/cmd/protoc-gen-openapi/main.go
@@ -38,6 +38,7 @@ func main() {
 		CircularDepth:   flags.Int("depth", 2, "depth of recursion for circular messages"),
 		DefaultResponse: flags.Bool("default_response", true, `add default response. If "true", automatically adds a default response to operations which use the google.rpc.Status message. Useful if you use envoy or grpc-gateway to transcode as they use this type for their default error responses.`),
 		OutputMode:      flags.String("output_mode", "merged", `output generation mode. By default, a single openapi.yaml is generated at the out folder. Use "source_relative' to generate a separate '[inputfile].openapi.yaml' next to each '[inputfile].proto'.`),
+		Int64AsString:   flags.Bool("int64_as_string", true, `serialize 64-bit integer types as string. If false, will serialize as integer which is incompatible with the official proto JSON serialization.`),
 	}
 
 	opts := protogen.Options{