diff --git a/mediapipe/calculators/tensorflow/unpack_media_sequence_calculator_test.cc b/mediapipe/calculators/tensorflow/unpack_media_sequence_calculator_test.cc
index b7a7d449..addb4a27 100644
--- a/mediapipe/calculators/tensorflow/unpack_media_sequence_calculator_test.cc
+++ b/mediapipe/calculators/tensorflow/unpack_media_sequence_calculator_test.cc
@@ -647,7 +647,7 @@ TEST_F(UnpackMediaSequenceCalculatorTest, GetAudioDecoderOptionsOverride) {
 
 TEST_F(UnpackMediaSequenceCalculatorTest, GetPacketResamplingOptions) {
   // TODO: Suport proto3 proto.Any in CalculatorOptions.
-  // TODO: Avoid google::protobuf extensions in "RESAMPLER_OPTIONS".
+  // TODO: Avoid proto2 extensions in "RESAMPLER_OPTIONS".
   CalculatorOptions options;
   options.MutableExtension(UnpackMediaSequenceCalculatorOptions::ext)
       ->set_padding_before_label(1);
diff --git a/mediapipe/framework/calculator_context_test.cc b/mediapipe/framework/calculator_context_test.cc
index 382c4c09..f9979a01 100644
--- a/mediapipe/framework/calculator_context_test.cc
+++ b/mediapipe/framework/calculator_context_test.cc
@@ -138,10 +138,10 @@ TEST(CalculatorTest, GetOptions) {
   EXPECT_FALSE(cc_3->HasOptions<NightLightCalculatorOptions>());
   EXPECT_TRUE(cc_3->HasOptions<SkyLightCalculatorOptions>());
 
-  // Get a google::protobuf options extension from Node::options.
+  // Get a proto2 options extension from Node::options.
   EXPECT_EQ(cc_0->Options<NightLightCalculatorOptions>().jitter(), 0.123);
 
-  // Get a google::protobuf options extension from Node::node_options.
+  // Get a proto2 options extension from Node::node_options.
   EXPECT_EQ(cc_1->Options<NightLightCalculatorOptions>().jitter(), 0.123);
 
   // Get a proto3 options protobuf::Any from Node::node_options.
diff --git a/mediapipe/framework/port/proto_ns.h b/mediapipe/framework/port/proto_ns.h
index 53b854ff..83aecdf4 100644
--- a/mediapipe/framework/port/proto_ns.h
+++ b/mediapipe/framework/port/proto_ns.h
@@ -17,9 +17,8 @@
 
 #include <string>
 
-// Temporary forward declarations for google::protobuf support on portable
-// targets. Use proto_ns inside namespace mediapipe instead of google::protobuf
-// namespace.
+// Temporary forward declarations for proto2 support on portable targets.
+// Use proto_ns inside namespace mediapipe instead of proto2 namespace.
 #include "google/protobuf/message.h"
 #include "google/protobuf/message_lite.h"
 #include "google/protobuf/repeated_field.h"
diff --git a/mediapipe/framework/tool/options_registry.h b/mediapipe/framework/tool/options_registry.h
index 3b2d2be8..b843b113 100644
--- a/mediapipe/framework/tool/options_registry.h
+++ b/mediapipe/framework/tool/options_registry.h
@@ -28,7 +28,7 @@ class OptionsRegistry {
   // Finds the descriptor for a protobuf.
   static const Descriptor* GetProtobufDescriptor(const std::string& type_name);
 
-  // Returns all known google::protobuf extensions to a type.
+  // Returns all known proto2 extensions to a type.
   static void FindAllExtensions(absl::string_view extendee,
                                 std::vector<const FieldDescriptor*>* result);