diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.js b/packages/react-reconciler/src/ReactFiberBeginWork.js
index f86a7baaff4a6..1e613daac5b04 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.js
@@ -3193,8 +3193,9 @@ function beginWork(
   }
   invariant(
     false,
-    'Unknown unit of work tag. This error is likely caused by a bug in ' +
+    'Unknown unit of work tag (%s). This error is likely caused by a bug in ' +
       'React. Please file an issue.',
+    workInProgress.tag,
   );
 }
 
diff --git a/packages/react-reconciler/src/ReactFiberCompleteWork.js b/packages/react-reconciler/src/ReactFiberCompleteWork.js
index 77dd42dfebd75..0a5f80010c325 100644
--- a/packages/react-reconciler/src/ReactFiberCompleteWork.js
+++ b/packages/react-reconciler/src/ReactFiberCompleteWork.js
@@ -1285,8 +1285,9 @@ function completeWork(
     default:
       invariant(
         false,
-        'Unknown unit of work tag. This error is likely caused by a bug in ' +
+        'Unknown unit of work tag (%s). This error is likely caused by a bug in ' +
           'React. Please file an issue.',
+        workInProgress.tag,
       );
   }
 
diff --git a/scripts/error-codes/codes.json b/scripts/error-codes/codes.json
index 00edb16006fa9..5d0a777457745 100644
--- a/scripts/error-codes/codes.json
+++ b/scripts/error-codes/codes.json
@@ -155,7 +155,7 @@
   "153": "Resuming work not yet implemented.",
   "154": "We should always have pending or current props. This error is likely caused by a bug in React. Please file an issue.",
   "155": "An indeterminate component should never have mounted. This error is likely caused by a bug in React. Please file an issue.",
-  "156": "Unknown unit of work tag. This error is likely caused by a bug in React. Please file an issue.",
+  "156": "Unknown unit of work tag (%s). This error is likely caused by a bug in React. Please file an issue.",
   "157": "Invalid type of work. This error is likely caused by a bug in React. Please file an issue.",
   "158": "There must be pending props for an initial mount. This error is likely caused by a bug in React. Please file an issue.",
   "159": "There should always be pending or memoized props. This error is likely caused by a bug in React. Please file an issue.",