diff --git a/src/mutator_test.cc b/src/mutator_test.cc
index fe93181..312b2d9 100644
--- a/src/mutator_test.cc
+++ b/src/mutator_test.cc
@@ -293,6 +293,14 @@ const char kOptionalInDeepAnyFields[] = R"(
   }
 )";
 
+const char kUnknownFieldInput[] = R"(
+  optional_bool: true
+  unknown_field: "test unknown field"
+)";
+
+const char kUnknownFieldExpected[] = R"(optional_bool: true
+)";
+
 class TestMutator : public Mutator {
  public:
   explicit TestMutator(bool keep_initialized,
@@ -668,6 +676,12 @@ TYPED_TEST(MutatorTypedTest, Serialization) {
   }
 }
 
+TYPED_TEST(MutatorTypedTest, UnknownFieldTextFormat) {
+  typename TestFixture::Message parsed;
+  EXPECT_TRUE(ParseTextMessage(kUnknownFieldInput, &parsed));
+  EXPECT_EQ(SaveMessageAsText(parsed), kUnknownFieldExpected);
+}
+
 TYPED_TEST(MutatorTypedTest, DeepRecursion) {
   typename TestFixture::Message message;
   typename TestFixture::Message* last = &message;
diff --git a/src/text_format.cc b/src/text_format.cc
index 94e6a79..4479229 100644
--- a/src/text_format.cc
+++ b/src/text_format.cc
@@ -30,6 +30,7 @@ bool ParseTextMessage(const std::string& data, protobuf::Message* output) {
   TextFormat::Parser parser;
   parser.SetRecursionLimit(100);
   parser.AllowPartialMessage(true);
+  parser.AllowUnknownField(true);
   if (!parser.ParseFromString(data, output)) {
     output->Clear();
     return false;