diff --git a/source/val/validate_extensions.cpp b/source/val/validate_extensions.cpp
index fe38f1f..f264c8e 100644
--- a/source/val/validate_extensions.cpp
+++ b/source/val/validate_extensions.cpp
@@ -21,6 +21,8 @@
 #include <vector>
 
 #include "source/diagnostic.h"
+#include "source/enum_string_mapping.h"
+#include "source/extensions.h"
 #include "source/latest_version_glsl_std_450_header.h"
 #include "source/latest_version_opencl_std_header.h"
 #include "source/opcode.h"
@@ -42,6 +44,21 @@
 
 }  // anonymous namespace
 
+spv_result_t ValidateExtension(ValidationState_t& _, const Instruction* inst) {
+  if (spvIsWebGPUEnv(_.context()->target_env)) {
+    std::string extension = GetExtensionString(&(inst->c_inst()));
+
+    if (extension != ExtensionToString(kSPV_KHR_vulkan_memory_model)) {
+      return _.diag(SPV_ERROR_INVALID_DATA, inst)
+             << "For WebGPU, the only valid parameter to OpExtension is "
+             << "\"" << ExtensionToString(kSPV_KHR_vulkan_memory_model)
+             << "\".";
+    }
+  }
+
+  return SPV_SUCCESS;
+}
+
 spv_result_t ValidateExtInstImport(ValidationState_t& _,
                                    const Instruction* inst) {
   if (spvIsWebGPUEnv(_.context()->target_env)) {
@@ -2001,6 +2018,7 @@
 
 spv_result_t ExtensionPass(ValidationState_t& _, const Instruction* inst) {
   const SpvOp opcode = inst->opcode();
+  if (opcode == SpvOpExtension) return ValidateExtension(_, inst);
   if (opcode == SpvOpExtInstImport) return ValidateExtInstImport(_, inst);
   if (opcode == SpvOpExtInst) return ValidateExtInst(_, inst);
 
diff --git a/test/val/val_webgpu_test.cpp b/test/val/val_webgpu_test.cpp
index ba59198..48ea21d 100644
--- a/test/val/val_webgpu_test.cpp
+++ b/test/val/val_webgpu_test.cpp
@@ -258,6 +258,24 @@
                         "OpExtInstImport \"OpenCL.std\"\n"));
 }
 
+TEST_F(ValidateWebGPU, NonVulkanKHRMemoryModelExtensionBad) {
+  std::string spirv = R"(
+     OpCapability Shader
+     OpCapability VulkanMemoryModelKHR
+     OpExtension "SPV_KHR_8bit_storage"
+     OpExtension "SPV_KHR_vulkan_memory_model"
+     OpMemoryModel Logical VulkanKHR
+)";
+
+  CompileSuccessfully(spirv);
+
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA, ValidateInstructions(SPV_ENV_WEBGPU_0));
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("For WebGPU, the only valid parameter to OpExtension "
+                        "is \"SPV_KHR_vulkan_memory_model\".\n  OpExtension "
+                        "\"SPV_KHR_8bit_storage\"\n"));
+}
+
 }  // namespace
 }  // namespace val
 }  // namespace spvtools