diff --git a/packages/pluggable-widgets-tools/CHANGELOG.md b/packages/pluggable-widgets-tools/CHANGELOG.md
index b84531e2..2a6848ca 100644
--- a/packages/pluggable-widgets-tools/CHANGELOG.md
+++ b/packages/pluggable-widgets-tools/CHANGELOG.md
@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Changed
+
+-   We now enforce the same validation for the `widgetName` in the widget bundler as we do in the generator.
+
 ## [11.3.0] - 2025-11-12
 
 ### Changed
diff --git a/packages/pluggable-widgets-tools/configs/shared.mjs b/packages/pluggable-widgets-tools/configs/shared.mjs
index 80098b07..e689ea95 100644
--- a/packages/pluggable-widgets-tools/configs/shared.mjs
+++ b/packages/pluggable-widgets-tools/configs/shared.mjs
@@ -24,6 +24,13 @@ export const widgetVersion = widgetPackageJson.version;
 if (!widgetName || !widgetPackageJson) {
     throw new Error("Widget does not define widgetName in its package.json");
 }
+if (!/^[a-zA-Z]+$/.test(widgetName)) {
+    const illegalChars = (widgetName.match(/[^a-zA-Z]/g) ?? [])
+        .reduce((unique, c) => unique.includes(c) ? unique : [...unique, c], [])
+        .map(c => `"${c}"`)
+        .join(", ");
+    throw new Error(`Widget contains unexpected character ${illegalChars} in its widgetName in package.json. Only lowercase and uppercase letters ([a-zA-Z]) are allowed.`);
+}
 
 const widgetSrcFiles = readdirSync(join(sourcePath, "src")).map(file => join(sourcePath, "src", file));
 export const widgetEntry = widgetSrcFiles.filter(file =>
diff --git a/packages/pluggable-widgets-tools/package.json b/packages/pluggable-widgets-tools/package.json
index 40efb0cf..6cab7627 100644
--- a/packages/pluggable-widgets-tools/package.json
+++ b/packages/pluggable-widgets-tools/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@mendix/pluggable-widgets-tools",
-  "version": "11.3.0",
+  "version": "11.3.1",
   "description": "Mendix Pluggable Widgets Tools",
   "engines": {
     "node": ">=20"