diff --git a/common/values/parsed_json_map_value.cc b/common/values/parsed_json_map_value.cc
index 6072a0b21..ec8c91a4f 100644
--- a/common/values/parsed_json_map_value.cc
+++ b/common/values/parsed_json_map_value.cc
@@ -408,8 +408,8 @@ class ParsedJsonMapValueIterator final : public ValueIterator {
  private:
   const google::protobuf::Message* absl_nonnull const message_;
   const well_known_types::StructReflection reflection_;
-  google::protobuf::MapIterator begin_;
-  const google::protobuf::MapIterator end_;
+  google::protobuf::ConstMapIterator begin_;
+  const google::protobuf::ConstMapIterator end_;
   std::string scratch_;
 };
 
diff --git a/common/values/parsed_map_field_value.cc b/common/values/parsed_map_field_value.cc
index 737593cca..47b737f82 100644
--- a/common/values/parsed_map_field_value.cc
+++ b/common/values/parsed_map_field_value.cc
@@ -415,10 +415,10 @@ absl::Status ParsedMapFieldValue::ListKeys(
                            field_->message_type()->map_key()));
   auto builder = NewListValueBuilder(arena);
   builder->Reserve(Size());
-  auto begin =
-      extensions::protobuf_internal::MapBegin(*reflection, *message_, *field_);
-  const auto end =
-      extensions::protobuf_internal::MapEnd(*reflection, *message_, *field_);
+  auto begin = extensions::protobuf_internal::ConstMapBegin(*reflection,
+                                                            *message_, *field_);
+  const auto end = extensions::protobuf_internal::ConstMapEnd(
+      *reflection, *message_, *field_);
   for (; begin != end; ++begin) {
     Value scratch;
     (*key_accessor)(begin.GetKey(), message_, arena, &scratch);
@@ -446,10 +446,10 @@ absl::Status ParsedMapFieldValue::ForEach(
     CEL_ASSIGN_OR_RETURN(
         auto value_accessor,
         common_internal::MapFieldValueAccessorFor(value_field));
-    auto begin = extensions::protobuf_internal::MapBegin(*reflection, *message_,
-                                                         *field_);
-    const auto end =
-        extensions::protobuf_internal::MapEnd(*reflection, *message_, *field_);
+    auto begin = extensions::protobuf_internal::ConstMapBegin(
+        *reflection, *message_, *field_);
+    const auto end = extensions::protobuf_internal::ConstMapEnd(
+        *reflection, *message_, *field_);
     Value key_scratch;
     Value value_scratch;
     for (; begin != end; ++begin) {
@@ -479,10 +479,10 @@ class ParsedMapFieldValueIterator final : public ValueIterator {
         value_field_(field->message_type()->map_value()),
         key_accessor_(key_accessor),
         value_accessor_(value_accessor),
-        begin_(extensions::protobuf_internal::MapBegin(
+        begin_(extensions::protobuf_internal::ConstMapBegin(
             *message_->GetReflection(), *message_, *field)),
-        end_(extensions::protobuf_internal::MapEnd(*message_->GetReflection(),
-                                                   *message_, *field)) {}
+        end_(extensions::protobuf_internal::ConstMapEnd(
+            *message_->GetReflection(), *message_, *field)) {}
 
   bool HasNext() override { return begin_ != end_; }
 
@@ -545,8 +545,8 @@ class ParsedMapFieldValueIterator final : public ValueIterator {
   const google::protobuf::FieldDescriptor* absl_nonnull const value_field_;
   const absl_nonnull common_internal::MapFieldKeyAccessor key_accessor_;
   const absl_nonnull common_internal::MapFieldValueAccessor value_accessor_;
-  google::protobuf::MapIterator begin_;
-  const google::protobuf::MapIterator end_;
+  google::protobuf::ConstMapIterator begin_;
+  const google::protobuf::ConstMapIterator end_;
 };
 
 }  // namespace
diff --git a/extensions/protobuf/internal/map_reflection.cc b/extensions/protobuf/internal/map_reflection.cc
index 22a6dc23c..605e4437d 100644
--- a/extensions/protobuf/internal/map_reflection.cc
+++ b/extensions/protobuf/internal/map_reflection.cc
@@ -42,22 +42,16 @@ class CelMapReflectionFriend final {
     return reflection.MapSize(message, &field);
   }
 
-  static google::protobuf::MapIterator MapBegin(const google::protobuf::Reflection& reflection,
-                                      const google::protobuf::Message& message,
-                                      const google::protobuf::FieldDescriptor& field) {
-    return reflection.MapBegin(
-        const_cast<  // NOLINT(google3-runtime-proto-const-cast)
-            google::protobuf::Message*>(&message),
-        &field);
+  static google::protobuf::ConstMapIterator ConstMapBegin(
+      const google::protobuf::Reflection& reflection, const google::protobuf::Message& message,
+      const google::protobuf::FieldDescriptor& field) {
+    return reflection.ConstMapBegin(&message, &field);
   }
 
-  static google::protobuf::MapIterator MapEnd(const google::protobuf::Reflection& reflection,
-                                    const google::protobuf::Message& message,
-                                    const google::protobuf::FieldDescriptor& field) {
-    return reflection.MapEnd(
-        const_cast<  // NOLINT(google3-runtime-proto-const-cast)
-            google::protobuf::Message*>(&message),
-        &field);
+  static google::protobuf::ConstMapIterator ConstMapEnd(
+      const google::protobuf::Reflection& reflection, const google::protobuf::Message& message,
+      const google::protobuf::FieldDescriptor& field) {
+    return reflection.ConstMapEnd(&message, &field);
   }
 
   static bool InsertOrLookupMapValue(const google::protobuf::Reflection& reflection,
@@ -104,18 +98,18 @@ int MapSize(const google::protobuf::Reflection& reflection,
                                                        field);
 }
 
-google::protobuf::MapIterator MapBegin(const google::protobuf::Reflection& reflection,
-                             const google::protobuf::Message& message,
-                             const google::protobuf::FieldDescriptor& field) {
-  return google::protobuf::expr::CelMapReflectionFriend::MapBegin(reflection, message,
-                                                        field);
+google::protobuf::ConstMapIterator ConstMapBegin(const google::protobuf::Reflection& reflection,
+                                       const google::protobuf::Message& message,
+                                       const google::protobuf::FieldDescriptor& field) {
+  return google::protobuf::expr::CelMapReflectionFriend::ConstMapBegin(reflection,
+                                                             message, field);
 }
 
-google::protobuf::MapIterator MapEnd(const google::protobuf::Reflection& reflection,
-                           const google::protobuf::Message& message,
-                           const google::protobuf::FieldDescriptor& field) {
-  return google::protobuf::expr::CelMapReflectionFriend::MapEnd(reflection, message,
-                                                      field);
+google::protobuf::ConstMapIterator ConstMapEnd(const google::protobuf::Reflection& reflection,
+                                     const google::protobuf::Message& message,
+                                     const google::protobuf::FieldDescriptor& field) {
+  return google::protobuf::expr::CelMapReflectionFriend::ConstMapEnd(reflection, message,
+                                                           field);
 }
 
 bool InsertOrLookupMapValue(const google::protobuf::Reflection& reflection,
diff --git a/extensions/protobuf/internal/map_reflection.h b/extensions/protobuf/internal/map_reflection.h
index 6e696bbe3..681d7693d 100644
--- a/extensions/protobuf/internal/map_reflection.h
+++ b/extensions/protobuf/internal/map_reflection.h
@@ -42,13 +42,13 @@ int MapSize(const google::protobuf::Reflection& reflection,
             const google::protobuf::Message& message,
             const google::protobuf::FieldDescriptor& field);
 
-google::protobuf::MapIterator MapBegin(const google::protobuf::Reflection& reflection,
-                             const google::protobuf::Message& message,
-                             const google::protobuf::FieldDescriptor& field);
+google::protobuf::ConstMapIterator ConstMapBegin(const google::protobuf::Reflection& reflection,
+                                       const google::protobuf::Message& message,
+                                       const google::protobuf::FieldDescriptor& field);
 
-google::protobuf::MapIterator MapEnd(const google::protobuf::Reflection& reflection,
-                           const google::protobuf::Message& message,
-                           const google::protobuf::FieldDescriptor& field);
+google::protobuf::ConstMapIterator ConstMapEnd(const google::protobuf::Reflection& reflection,
+                                     const google::protobuf::Message& message,
+                                     const google::protobuf::FieldDescriptor& field);
 
 bool InsertOrLookupMapValue(const google::protobuf::Reflection& reflection,
                             google::protobuf::Message* message,
diff --git a/internal/json.cc b/internal/json.cc
index 200d18bfb..630ceb267 100644
--- a/internal/json.cc
+++ b/internal/json.cc
@@ -803,10 +803,10 @@ class MessageToJsonState {
     const auto* value_descriptor = field->message_type()->map_value();
     CEL_ASSIGN_OR_RETURN(const auto value_to_value,
                          GetMapFieldValueToValue(value_descriptor));
-    auto begin =
-        extensions::protobuf_internal::MapBegin(*reflection, message, *field);
-    const auto end =
-        extensions::protobuf_internal::MapEnd(*reflection, message, *field);
+    auto begin = extensions::protobuf_internal::ConstMapBegin(*reflection,
+                                                              message, *field);
+    const auto end = extensions::protobuf_internal::ConstMapEnd(
+        *reflection, message, *field);
     for (; begin != end; ++begin) {
       auto key = (*key_to_string)(begin.GetKey());
       CEL_RETURN_IF_ERROR((this->*value_to_value)(
@@ -1381,7 +1381,7 @@ class JsonMapIterator final {
   using Generated =
       typename google::protobuf::Map<std::string,
                            google::protobuf::Value>::const_iterator;
-  using Dynamic = google::protobuf::MapIterator;
+  using Dynamic = google::protobuf::ConstMapIterator;
   using Value = std::pair<well_known_types::StringValue,
                           const google::protobuf::MessageLite* absl_nonnull>;
 
diff --git a/internal/message_equality.cc b/internal/message_equality.cc
index 628432d66..945cca8df 100644
--- a/internal/message_equality.cc
+++ b/internal/message_equality.cc
@@ -50,9 +50,9 @@ namespace cel::internal {
 
 namespace {
 
+using ::cel::extensions::protobuf_internal::ConstMapBegin;
+using ::cel::extensions::protobuf_internal::ConstMapEnd;
 using ::cel::extensions::protobuf_internal::LookupMapValue;
-using ::cel::extensions::protobuf_internal::MapBegin;
-using ::cel::extensions::protobuf_internal::MapEnd;
 using ::cel::extensions::protobuf_internal::MapSize;
 using ::google::protobuf::Descriptor;
 using ::google::protobuf::DescriptorPool;
@@ -904,8 +904,8 @@ class MessageEqualsState final {
         MapSize(*rhs_reflection, rhs, *rhs_field)) {
       return false;
     }
-    auto lhs_begin = MapBegin(*lhs_reflection, lhs, *lhs_field);
-    const auto lhs_end = MapEnd(*lhs_reflection, lhs, *lhs_field);
+    auto lhs_begin = ConstMapBegin(*lhs_reflection, lhs, *lhs_field);
+    const auto lhs_end = ConstMapEnd(*lhs_reflection, lhs, *lhs_field);
     Unique<Message> lhs_unpacked;
     EquatableValue lhs_value;
     Unique<Message> rhs_unpacked;
diff --git a/internal/well_known_types.cc b/internal/well_known_types.cc
index c736be69f..dee029534 100644
--- a/internal/well_known_types.cc
+++ b/internal/well_known_types.cc
@@ -1643,20 +1643,20 @@ int StructReflection::FieldsSize(const google::protobuf::Message& message) const
                                                      message, *fields_field_);
 }
 
-google::protobuf::MapIterator StructReflection::BeginFields(
+google::protobuf::ConstMapIterator StructReflection::BeginFields(
     const google::protobuf::Message& message) const {
   ABSL_DCHECK(IsInitialized());
   ABSL_DCHECK_EQ(message.GetDescriptor(), descriptor_);
-  return cel::extensions::protobuf_internal::MapBegin(*message.GetReflection(),
-                                                      message, *fields_field_);
+  return cel::extensions::protobuf_internal::ConstMapBegin(
+      *message.GetReflection(), message, *fields_field_);
 }
 
-google::protobuf::MapIterator StructReflection::EndFields(
+google::protobuf::ConstMapIterator StructReflection::EndFields(
     const google::protobuf::Message& message) const {
   ABSL_DCHECK(IsInitialized());
   ABSL_DCHECK_EQ(message.GetDescriptor(), descriptor_);
-  return cel::extensions::protobuf_internal::MapEnd(*message.GetReflection(),
-                                                    message, *fields_field_);
+  return cel::extensions::protobuf_internal::ConstMapEnd(
+      *message.GetReflection(), message, *fields_field_);
 }
 
 bool StructReflection::ContainsField(const google::protobuf::Message& message,
diff --git a/internal/well_known_types.h b/internal/well_known_types.h
index dce88a420..f63e5e76b 100644
--- a/internal/well_known_types.h
+++ b/internal/well_known_types.h
@@ -698,8 +698,9 @@ absl::StatusOr<AnyReflection> GetAnyReflection(
     const google::protobuf::Descriptor* absl_nonnull descriptor
         ABSL_ATTRIBUTE_LIFETIME_BOUND);
 
-AnyReflection GetAnyReflectionOrDie(const google::protobuf::Descriptor* absl_nonnull
-                                    descriptor ABSL_ATTRIBUTE_LIFETIME_BOUND);
+AnyReflection GetAnyReflectionOrDie(
+    const google::protobuf::Descriptor* absl_nonnull descriptor
+        ABSL_ATTRIBUTE_LIFETIME_BOUND);
 
 class DurationReflection final {
  public:
@@ -1193,10 +1194,10 @@ class StructReflection final {
 
   int FieldsSize(const google::protobuf::Message& message) const;
 
-  google::protobuf::MapIterator BeginFields(
+  google::protobuf::ConstMapIterator BeginFields(
       const google::protobuf::Message& message ABSL_ATTRIBUTE_LIFETIME_BOUND) const;
 
-  google::protobuf::MapIterator EndFields(
+  google::protobuf::ConstMapIterator EndFields(
       const google::protobuf::Message& message ABSL_ATTRIBUTE_LIFETIME_BOUND) const;
 
   bool ContainsField(const google::protobuf::Message& message,