diff --git a/tfjs-backend-wasm/src/cc/BUILD.bazel b/tfjs-backend-wasm/src/cc/BUILD.bazel
index 48b423f7754..2ab146dc8c8 100644
--- a/tfjs-backend-wasm/src/cc/BUILD.bazel
+++ b/tfjs-backend-wasm/src/cc/BUILD.bazel
@@ -661,6 +661,15 @@ tfjs_unit_test(
     ],
 )
 
+tfjs_cc_library(
+    name = "Diag",
+    srcs = ["kernels/Diag.cc"],
+    deps = [
+        ":backend",
+        ":util",
+    ],
+)
+
 tfjs_cc_library(
     name = "RealDiv",
     srcs = ["kernels/RealDiv.cc"],
diff --git a/tfjs-backend-wasm/src/cc/kernels/Diag.cc b/tfjs-backend-wasm/src/cc/kernels/Diag.cc
new file mode 100644
index 00000000000..99cf94d0641
--- /dev/null
+++ b/tfjs-backend-wasm/src/cc/kernels/Diag.cc
@@ -0,0 +1,71 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * =============================================================================
+ */
+
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
+#include <algorithm>
+#include <cmath>
+
+#include "tfjs-backend-wasm/src/cc/backend.h"
+#include "tfjs-backend-wasm/src/cc/util.h"
+
+namespace tfjs {
+namespace wasm {
+
+namespace {
+
+template <typename T>
+inline void DiagImpl(const T* x_buf, int32_t x_size, T* out_buf) {
+  std::fill(out_buf, out_buf + x_size * x_size, 0);
+  for (int32_t i = 0; i < x_size; ++i) {
+    out_buf[x_size * i + i] = x_buf[i];
+  }
+}
+
+}  // namespace
+
+// We use C-style API to interface with Javascript.
+extern "C" {
+
+#ifdef __EMSCRIPTEN__
+EMSCRIPTEN_KEEPALIVE
+#endif
+void Diag(const int32_t x_id, const DType dtype, const int32_t x_size,
+          const int32_t out_id) {
+  const TensorInfo& x_info = backend::get_tensor_info(x_id);
+  TensorInfo& out_info = backend::get_tensor_info_out(out_id);
+  switch (dtype) {
+    case DType::float32:
+      DiagImpl(x_info.f32(), x_size, out_info.f32_write());
+      break;
+    case DType::int32:
+      DiagImpl(x_info.i32(), x_size, out_info.i32_write());
+      break;
+    case DType::boolean:
+      DiagImpl(x_info.b(), x_size, out_info.b_write());
+      break;
+    default:
+      util::warn("Diag for tensor id %d failed. Unsupported dtype %d", x_id,
+                 dtype);
+  }
+}
+
+}  // extern "C"
+}  // namespace wasm
+}  // namespace tfjs
diff --git a/tfjs-backend-wasm/src/kernels/Diag.ts b/tfjs-backend-wasm/src/kernels/Diag.ts
new file mode 100644
index 00000000000..c1266d1389a
--- /dev/null
+++ b/tfjs-backend-wasm/src/kernels/Diag.ts
@@ -0,0 +1,55 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * =============================================================================
+ */
+
+import {Diag, DiagInputs, KernelConfig, KernelFunc, TensorInfo, util} from '@tensorflow/tfjs-core';
+
+import {BackendWasm} from '../backend_wasm';
+
+import {CppDType} from './types';
+
+let wasmDiag: (xId: number, xDType: CppDType, xSize: number, outId: number) =>
+    void;
+
+function setup(backend: BackendWasm) {
+  wasmDiag = backend.wasm.cwrap('Diag', null, [
+    'number',  // xId
+    'number',  // xDType,
+    'number',  // xSize,
+    'number',  // outId
+  ]);
+}
+
+export function diag(args: {inputs: DiagInputs, backend: BackendWasm}):
+    TensorInfo {
+  const {inputs, backend} = args;
+  const {x} = inputs;
+
+  const xSize = util.sizeFromShape(x.shape);
+  const out = backend.makeOutput([...x.shape, ...x.shape], x.dtype);
+
+  wasmDiag(
+      backend.dataIdMap.get(x.dataId).id, CppDType[x.dtype], xSize,
+      backend.dataIdMap.get(out.dataId).id);
+  return out;
+}
+
+export const diagConfig: KernelConfig = {
+  kernelName: Diag,
+  backendName: 'wasm',
+  setupFunc: setup,
+  kernelFunc: diag as unknown as KernelFunc
+};
diff --git a/tfjs-backend-wasm/src/register_all_kernels.ts b/tfjs-backend-wasm/src/register_all_kernels.ts
index cc519fce755..74ca2dd8e22 100644
--- a/tfjs-backend-wasm/src/register_all_kernels.ts
+++ b/tfjs-backend-wasm/src/register_all_kernels.ts
@@ -47,6 +47,7 @@ import {cumprodConfig} from './kernels/Cumprod';
 import {cumsumConfig} from './kernels/Cumsum';
 import {depthToSpaceConfig} from './kernels/DepthToSpace';
 import {depthwiseConv2dNativeConfig} from './kernels/DepthwiseConv2dNative';
+import {diagConfig} from './kernels/Diag';
 import {eluConfig} from './kernels/Elu';
 import {equalConfig} from './kernels/Equal';
 import {expConfig} from './kernels/Exp';
@@ -166,6 +167,7 @@ const kernelConfigs: KernelConfig[] = [
   cumsumConfig,
   depthToSpaceConfig,
   depthwiseConv2dNativeConfig,
+  diagConfig,
   eluConfig,
   equalConfig,
   expConfig,
diff --git a/tfjs-backend-wasm/src/setup_test.ts b/tfjs-backend-wasm/src/setup_test.ts
index 34e975ebea2..11cde009c6a 100644
--- a/tfjs-backend-wasm/src/setup_test.ts
+++ b/tfjs-backend-wasm/src/setup_test.ts
@@ -407,6 +407,7 @@ const TEST_FILTERS: TestFilter[] = [
   {include: 'acosh '},
   {include: 'asin '},
   {include: 'asinh '},
+  {include: 'diag '},
 ];
 
 const customInclude = (testName: string) => {