diff --git a/ReactCommon/jserrorhandler/BUCK b/ReactCommon/jserrorhandler/BUCK
index 9edd6729f64..da94ec52fa6 100644
--- a/ReactCommon/jserrorhandler/BUCK
+++ b/ReactCommon/jserrorhandler/BUCK
@@ -1,4 +1,4 @@
-load("//tools/build_defs/oss:rn_defs.bzl", "ANDROID", "APPLE", "CXX", "react_native_xplat_target", "rn_xplat_cxx_library")
+load("//tools/build_defs/oss:rn_defs.bzl", "ANDROID", "APPLE", "CXX", "fb_xplat_cxx_test", "react_native_xplat_target", "rn_xplat_cxx_library")
 
 # TODO: Expolre merging this module into venice so we don't to load this library seperately
 rn_xplat_cxx_library(
@@ -18,6 +18,7 @@ rn_xplat_cxx_library(
         "-DLOG_TAG=\"ReactNative\"",
         "-DWITH_FBSYSTRACE=1",
     ],
+    tests = [":tests"],
     visibility = [
         "PUBLIC",
     ],
@@ -28,3 +29,23 @@ rn_xplat_cxx_library(
         react_native_xplat_target("react/renderer/mapbuffer:mapbuffer"),
     ],
 )
+
+fb_xplat_cxx_test(
+    name = "tests",
+    srcs = glob(["tests/**/*.cpp"]),
+    headers = glob(["tests/**/*.h"]),
+    compiler_flags = [
+        "-fexceptions",
+        "-frtti",
+        "-std=c++17",
+        "-Wall",
+    ],
+    contacts = ["oncall+react_native@xmail.facebook.com"],
+    platforms = (ANDROID, APPLE, CXX),
+    deps = [
+        "//xplat/hermes/API:HermesAPI",
+        "//xplat/third-party/gmock:gtest",
+        react_native_xplat_target("jserrorhandler:jserrorhandler"),
+        react_native_xplat_target("react/renderer/mapbuffer:mapbuffer"),
+    ],
+)
diff --git a/ReactCommon/jserrorhandler/tests/JsErrorHandlerTest.cpp b/ReactCommon/jserrorhandler/tests/JsErrorHandlerTest.cpp
new file mode 100644
index 00000000000..44af20161b5
--- /dev/null
+++ b/ReactCommon/jserrorhandler/tests/JsErrorHandlerTest.cpp
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <memory>
+#include <vector>
+
+#include <gtest/gtest.h>
+#include <hermes/API/hermes/hermes.h>
+#include <jserrorhandler/JsErrorHandler.h>
+#include <jsi/jsi.h>
+#include <react/renderer/mapbuffer/MapBuffer.h>
+#include <react/renderer/mapbuffer/MapBufferBuilder.h>
+
+namespace facebook::react {
+
+class JsErrorHandlerTest : public testing::Test {
+  void SetUp() override {
+    runtime_ = facebook::hermes::makeHermesRuntime();
+  }
+
+ protected:
+  MapBuffer parseErrorWithStackString(std::string stack, bool isFatal) {
+    std::optional<MapBuffer> result;
+    JsErrorHandler handler{
+        [&](MapBuffer errorMap) -> void { result = std::move(errorMap); }};
+    jsi::JSError error{*runtime_, "test message", stack};
+    handler.handleJsError(error, isFatal);
+    EXPECT_TRUE(result.has_value());
+    return std::move(*result);
+  }
+
+ private:
+  std::unique_ptr<facebook::hermes::HermesRuntime> runtime_;
+};
+
+TEST_F(JsErrorHandlerTest, testSimpleJscSourceStack) {
+  auto errorMap = parseErrorWithStackString(
+      "http://path/to/file.js:47:22\n"
+      "foo@http://path/to/file.js:52:15\n"
+      "bar@http://path/to/file.js:108:23",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 3);
+
+  EXPECT_EQ(
+      frames[0].getString(JSErrorHandlerKey::kFrameFileName),
+      "http://path/to/file.js");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 47);
+  // TODO: This is the wrong column number. JSC's columns are 1-based while ours
+  // are 0-based.
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 22);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "");
+
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName),
+      "http://path/to/file.js");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 52);
+  // TODO: This is the wrong column number. JSC's columns are 1-based while ours
+  // are 0-based.
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 15);
+  EXPECT_EQ(frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "foo");
+
+  EXPECT_EQ(
+      frames[2].getString(JSErrorHandlerKey::kFrameFileName),
+      "http://path/to/file.js");
+  EXPECT_EQ(frames[2].getInt(JSErrorHandlerKey::kFrameLineNumber), 108);
+  // TODO: This is the wrong column number. JSC's columns are 1-based while ours
+  // are 0-based.
+  EXPECT_EQ(frames[2].getInt(JSErrorHandlerKey::kFrameColumnNumber), 23);
+  EXPECT_EQ(frames[2].getString(JSErrorHandlerKey::kFrameMethodName), "bar");
+}
+
+TEST_F(JsErrorHandlerTest, testSimpleHermesBytecodeStack) {
+  auto errorMap = parseErrorWithStackString(
+      "    at global (address at unknown:1:9)\n"
+      "    at foo$bar (address at /js/foo.hbc:10:1234)",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 2);
+
+  // TODO: This is the wrong source URL.
+  EXPECT_EQ(
+      frames[0].getString(JSErrorHandlerKey::kFrameFileName),
+      "address at unknown");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 1);
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 9);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "global");
+
+  // TODO: This is the wrong source URL.
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName),
+      "address at /js/foo.hbc");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 10);
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 1234);
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "foo$bar");
+}
+
+TEST_F(JsErrorHandlerTest, testSimpleHermesSourceStack) {
+  auto errorMap = parseErrorWithStackString(
+      "    at global (unknown:1:9)\n"
+      "    at foo$bar (/js/foo.js:10:1234)",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 2);
+
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameFileName), "unknown");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 1);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 9);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "global");
+
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName), "/js/foo.js");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 10);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 1234);
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "foo$bar");
+}
+
+TEST_F(JsErrorHandlerTest, testHermesSourceStackWithSkippedFrames) {
+  auto errorMap = parseErrorWithStackString(
+      "    at global (unknown:1:9)\n"
+      "    ... skipping 50 frames\n"
+      "    at foo$bar (/js/foo.js:10:1234)",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 2);
+
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameFileName), "unknown");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 1);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 9);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "global");
+
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName), "/js/foo.js");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 10);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 1234);
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "foo$bar");
+}
+
+TEST_F(JsErrorHandlerTest, testHermesSourceStackWithNativeFrame) {
+  auto errorMap = parseErrorWithStackString(
+      "    at global (unknown:1:9)\n"
+      "    at apply (native)\n"
+      "    at foo$bar (/js/foo.js:10:1234)",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 2);
+
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameFileName), "unknown");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 1);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 9);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "global");
+
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName), "/js/foo.js");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 10);
+  // TODO: This is the wrong column number. Hermes's columns are 1-based (for
+  // non-bytecode locations) while ours are 0-based.
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 1234);
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "foo$bar");
+}
+
+TEST_F(JsErrorHandlerTest, testJsxSourceStackWithEval) {
+  auto errorMap = parseErrorWithStackString(
+      "eval code\n"
+      "eval@[native code]\n"
+      "foo@http://path/to/file.js:58:21\n"
+      "bar@http://path/to/file.js:109:91",
+      /* isFatal */ false);
+
+  EXPECT_FALSE(errorMap.getBool(JSErrorHandlerKey::kIsFatal));
+
+  auto frames = errorMap.getMapBufferList(JSErrorHandlerKey::kAllStackFrames);
+  EXPECT_EQ(frames.size(), 2);
+
+  EXPECT_EQ(
+      frames[0].getString(JSErrorHandlerKey::kFrameFileName),
+      "http://path/to/file.js");
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameLineNumber), 58);
+  // TODO: This is the wrong column number. JSC's columns are 1-based while ours
+  // are 0-based.
+  EXPECT_EQ(frames[0].getInt(JSErrorHandlerKey::kFrameColumnNumber), 21);
+  EXPECT_EQ(frames[0].getString(JSErrorHandlerKey::kFrameMethodName), "foo");
+
+  EXPECT_EQ(
+      frames[1].getString(JSErrorHandlerKey::kFrameFileName),
+      "http://path/to/file.js");
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameLineNumber), 109);
+  // TODO: This is the wrong column number. JSC's columns are 1-based while ours
+  // are 0-based.
+  EXPECT_EQ(frames[1].getInt(JSErrorHandlerKey::kFrameColumnNumber), 91);
+  EXPECT_EQ(frames[1].getString(JSErrorHandlerKey::kFrameMethodName), "bar");
+}
+} // namespace facebook::react