diff --git a/conformance/BUILD.bazel b/conformance/BUILD.bazel
index ae9c18c0ed..384bb56563 100644
--- a/conformance/BUILD.bazel
+++ b/conformance/BUILD.bazel
@@ -178,6 +178,7 @@ cc_library(
         "@com_google_absl//absl/log:die_if_null",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:str_format",
         "@jsoncpp",
     ],
 )
diff --git a/conformance/binary_json_conformance_suite.cc b/conformance/binary_json_conformance_suite.cc
index fd21da7212..bd0f59b012 100644
--- a/conformance/binary_json_conformance_suite.cc
+++ b/conformance/binary_json_conformance_suite.cc
@@ -22,6 +22,7 @@
 #include "absl/log/die_if_null.h"
 #include "absl/status/status.h"
 #include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"
 #include "absl/strings/substitute.h"
 #include "conformance/conformance.pb.h"
@@ -1303,6 +1304,24 @@ void BinaryAndJsonConformanceSuiteImpl<MessageType>::TestIllegalTags() {
   }
 }
 
+template <typename MessageType>
+void BinaryAndJsonConformanceSuiteImpl<MessageType>::TestUnknownWireType() {
+  for (uint8_t type : {0x6, 0x7}) {
+    for (uint8_t field = 0; field < 4; ++field) {
+      for (uint8_t value = 0; value < 4; ++value) {
+        std::string name = absl::StrFormat("UnknownWireType%d_Field%d_Verion%d",
+                                           type, field, value);
+
+        char data[2];
+        data[0] = (field << 3) | type;  // unknown wire type.
+        data[1] = value;
+        std::string proto = {data, 2};
+        ExpectParseFailureForProto(proto, name, REQUIRED);
+      }
+    }
+  }
+}
+
 template <typename MessageType>
 void BinaryAndJsonConformanceSuiteImpl<MessageType>::TestOneofMessage() {
   MessageType message;
@@ -1467,6 +1486,8 @@ void BinaryAndJsonConformanceSuiteImpl<MessageType>::RunAllTests() {
 
     TestIllegalTags();
 
+    TestUnknownWireType();
+
     int64_t kInt64Min = -9223372036854775808ULL;
     int64_t kInt64Max = 9223372036854775807ULL;
     uint64_t kUint64Max = 18446744073709551615ULL;
diff --git a/conformance/binary_json_conformance_suite.h b/conformance/binary_json_conformance_suite.h
index a510e9a6b8..325a76e3ba 100644
--- a/conformance/binary_json_conformance_suite.h
+++ b/conformance/binary_json_conformance_suite.h
@@ -143,6 +143,7 @@ class BinaryAndJsonConformanceSuiteImpl {
                                       ConformanceLevel level);
   void TestPrematureEOFForType(google::protobuf::FieldDescriptor::Type type);
   void TestIllegalTags();
+  void TestUnknownWireType();
   void TestOneofMessage();
   void TestUnknownMessage();
   void TestUnknownOrdering();