diff --git a/.changeset/new-students-brush.md b/.changeset/new-students-brush.md
new file mode 100644
index 00000000..159ceba2
--- /dev/null
+++ b/.changeset/new-students-brush.md
@@ -0,0 +1,5 @@
+---
+'@myst-theme/jupyter': patch
+---
+
+Fix path of non-ipynb files in thebe
diff --git a/packages/jupyter/src/execute/leaf.tsx b/packages/jupyter/src/execute/leaf.tsx
index cda43707..7340aa63 100644
--- a/packages/jupyter/src/execute/leaf.tsx
+++ b/packages/jupyter/src/execute/leaf.tsx
@@ -140,9 +140,10 @@ export function SessionStarter({
       // in order to allow for multiple independent sessions of the same notebook
       let path = `/${pageSlug}-${notebookSlug}.ipynb`;
       console.debug('session starter path:', path);
-      const match = location?.match(/(.*)\/.*.ipynb$/) ?? null;
+      const match = location?.match(/(.*)\/.*/) ?? null;
       if (match) {
         console.debug('session starter match:', match);
+        // Choose an arbitrary suffix, not important
         path = `${match[1]}/${pageSlug}-${notebookSlug}.ipynb`;
         console.debug('session starter path (modified):', path);
       }