diff --git a/packages/react-native/ReactCommon/react/runtime/TimerManager.cpp b/packages/react-native/ReactCommon/react/runtime/TimerManager.cpp
index 5514a268370..da81670bb45 100644
--- a/packages/react-native/ReactCommon/react/runtime/TimerManager.cpp
+++ b/packages/react-native/ReactCommon/react/runtime/TimerManager.cpp
@@ -300,8 +300,9 @@ void TimerManager::attachGlobals(jsi::Runtime& runtime) {
             }
 
             if (!args[0].isObject() || !args[0].asObject(rt).isFunction(rt)) {
-              // Do not throw any error to match web spec
-              return timerIndex_++;
+              // Do not throw any error to match web spec; instead return 0, an
+              // invalid timer id
+              return 0;
             }
 
             auto callback = args[0].getObject(rt).getFunction(rt);
@@ -358,8 +359,9 @@ void TimerManager::attachGlobals(jsi::Runtime& runtime) {
             }
 
             if (!args[0].isObject() || !args[0].asObject(rt).isFunction(rt)) {
-              throw jsi::JSError(
-                  rt, "The first argument to setInterval must be a function.");
+              // Do not throw any error to match web spec; instead return 0, an
+              // invalid timer id
+              return 0;
             }
             auto callback = args[0].getObject(rt).getFunction(rt);
             auto delay = count > 1
diff --git a/packages/react-native/ReactCommon/react/runtime/TimerManager.h b/packages/react-native/ReactCommon/react/runtime/TimerManager.h
index 879ba30430a..914dec0b167 100644
--- a/packages/react-native/ReactCommon/react/runtime/TimerManager.h
+++ b/packages/react-native/ReactCommon/react/runtime/TimerManager.h
@@ -93,7 +93,9 @@ class TimerManager {
 
   // Each timeout that is registered on this queue gets a sequential id.  This
   // is the global count from which those are assigned.
-  TimerHandle timerIndex_{0};
+  // As per WHATWG HTML 8.6.1 (Timers) ids must be greater than zero, i.e. start
+  // at 1
+  TimerHandle timerIndex_{1};
 
   // The React Native microtask queue is used to back public APIs including
   // `queueMicrotask`, `clearImmediate`, and `setImmediate` (which is used by
diff --git a/packages/react-native/ReactCommon/react/runtime/tests/cxx/ReactInstanceTest.cpp b/packages/react-native/ReactCommon/react/runtime/tests/cxx/ReactInstanceTest.cpp
index 6e93d7a2b8a..63b5aa4a385 100644
--- a/packages/react-native/ReactCommon/react/runtime/tests/cxx/ReactInstanceTest.cpp
+++ b/packages/react-native/ReactCommon/react/runtime/tests/cxx/ReactInstanceTest.cpp
@@ -267,7 +267,9 @@ TEST_F(ReactInstanceTest, testSetTimeoutWithoutDelay) {
   EXPECT_CALL(
       *mockRegistry_,
       createTimer(_, 0)); // If delay is not provided, it should use 0
-  eval("setTimeout(() => {});");
+  auto val = eval("setTimeout(() => {});");
+  expectNoError();
+  EXPECT_EQ(val.asNumber(), 1); // First timer id should start at 1
 }
 
 TEST_F(ReactInstanceTest, testSetTimeoutWithPassThroughArgs) {
@@ -299,8 +301,9 @@ TEST_F(ReactInstanceTest, testSetTimeoutWithInvalidArgs) {
       getErrorMessage("setTimeout();"),
       "setTimeout must be called with at least one argument (the function to call).");
 
-  eval("setTimeout('invalid');");
+  auto val = eval("setTimeout('invalid')");
   expectNoError();
+  EXPECT_EQ(val.asNumber(), 0);
 
   eval("setTimeout(() => {}, 'invalid');");
   expectNoError();
@@ -417,9 +420,10 @@ TEST_F(ReactInstanceTest, testSetIntervalWithInvalidArgs) {
   EXPECT_EQ(
       getErrorMessage("setInterval();"),
       "setInterval must be called with at least one argument (the function to call).");
-  EXPECT_EQ(
-      getErrorMessage("setInterval('invalid', 100);"),
-      "The first argument to setInterval must be a function.");
+
+  auto val = eval("setInterval('invalid', 100)");
+  expectNoError();
+  EXPECT_EQ(val.asNumber(), 0);
 }
 
 TEST_F(ReactInstanceTest, testClearInterval) {