diff --git a/apps/staged/src/lib/features/diff/DiffModal.svelte b/apps/staged/src/lib/features/diff/DiffModal.svelte
index f0f4d34f..e97ec697 100644
--- a/apps/staged/src/lib/features/diff/DiffModal.svelte
+++ b/apps/staged/src/lib/features/diff/DiffModal.svelte
@@ -214,6 +214,9 @@
     // Reset review state — the $effect will recreate it once the new commitSha resolves
     reviewHandle = null;
 
+    // Reset so the sidebar-order effect picks the first file after reload
+    initialSelectionApplied = false;
+
     // Switch diff context (reloads file list)
     try {
       await diffViewer.switchContext(newScope, newCommitSha);
@@ -740,6 +743,23 @@
       : [...flattenTreeFiles(needsReviewTree), ...flattenTreeFiles(reviewedTree)]
   );
 
+  // Once files finish loading, override the initial selection with the first
+  // file in sidebar order so the viewer and sidebar stay in sync.
+  // For non-readonly reviews, also wait for reviewedPaths to load so the
+  // needs-review / reviewed split is accurate before picking the first file.
+  let initialSelectionApplied = false;
+  $effect(() => {
+    if (
+      !diffViewer.state.loading &&
+      orderedFiles.length > 0 &&
+      !initialSelectionApplied &&
+      (readonly || !reviewHandle || !reviewHandle.state.loading)
+    ) {
+      initialSelectionApplied = true;
+      diffViewer.selectFile(orderedFiles[0].path);
+    }
+  });
+
   // ==========================================================================
   // Sidebar interactions
   // ==========================================================================