diff --git a/packages/wp-build/CHANGELOG.md b/packages/wp-build/CHANGELOG.md
index 30aaec0c61932d..6e08d98f9a2607 100644
--- a/packages/wp-build/CHANGELOG.md
+++ b/packages/wp-build/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Breaking Changes
+
+-   `@wordpress/build` no longer parses JSX syntax in `.js` source files. Rename these files to `.jsx` or `.tsx` before building ([#82189](https://github.com/WordPress/gutenberg/pull/82189)).
+
 ### Enhancements
 
 -   Target `@wordpress/browserslist-config` for JavaScript and CSS when the project has no Browserslist config, instead of Browserslist's implicit defaults ([#82179](https://github.com/WordPress/gutenberg/pull/82179)).
diff --git a/packages/wp-build/lib/build.mjs b/packages/wp-build/lib/build.mjs
index e7c77f50625628..baefec0773e8ce 100755
--- a/packages/wp-build/lib/build.mjs
+++ b/packages/wp-build/lib/build.mjs
@@ -1489,7 +1489,6 @@ async function transpilePackage( packageName ) {
 				target,
 				jsx: 'automatic',
 				jsxImportSource: 'react',
-				loader: { '.js': 'jsx' },
 				plugins,
 			} )
 		);
@@ -1523,7 +1522,6 @@ async function transpilePackage( packageName ) {
 				target,
 				jsx: 'automatic',
 				jsxImportSource: 'react',
-				loader: { '.js': 'jsx' },
 				plugins,
 			} )
 		);
diff --git a/packages/wp-build/lib/worker-build.mjs b/packages/wp-build/lib/worker-build.mjs
index 9f771e30b8084a..a820a11525bc52 100644
--- a/packages/wp-build/lib/worker-build.mjs
+++ b/packages/wp-build/lib/worker-build.mjs
@@ -333,7 +333,6 @@ export const workerCode = ${ JSON.stringify( workerContent ) };
 				target,
 				jsx: 'automatic',
 				jsxImportSource: 'react',
-				loader: { '.js': 'jsx' },
 				plugins,
 			} )
 		);
@@ -356,7 +355,6 @@ export const workerCode = ${ JSON.stringify( workerContent ) };
 				target,
 				jsx: 'automatic',
 				jsxImportSource: 'react',
-				loader: { '.js': 'jsx' },
 				plugins,
 			} )
 		);