diff --git a/apps/web/components/task/file-browser-parts.tsx b/apps/web/components/task/file-browser-parts.tsx
index da056ae8e2..9746438c89 100644
--- a/apps/web/components/task/file-browser-parts.tsx
+++ b/apps/web/components/task/file-browser-parts.tsx
@@ -120,9 +120,12 @@ function TreeNodeChildren({ props, depth }: { props: TreeNodeItemProps; depth: n
           onCancel={onCancelCreate}
         />
       )}
-      {node.children?.map((child) => (
-        <TreeNodeItem key={child.path} {...props} node={child} depth={depth + 1} />
-      ))}
+      {node.children &&
+        [...node.children]
+          .sort(compareTreeNodes)
+          .map((child) => (
+            <TreeNodeItem key={child.path} {...props} node={child} depth={depth + 1} />
+          ))}
     </div>
   );
 }
@@ -142,6 +145,9 @@ export function TreeNodeItem(props: TreeNodeItemProps) {
 
   const rowContent = (
     <div
+      data-testid="file-tree-node"
+      data-path={node.path}
+      data-is-dir={node.is_dir ? "true" : "false"}
       className={cn(
         "group flex w-full items-center gap-1 px-2 py-0.5 text-left text-sm cursor-pointer",
         "hover:bg-muted",
diff --git a/apps/web/e2e/tests/task/file-tree-sorting.spec.ts b/apps/web/e2e/tests/task/file-tree-sorting.spec.ts
new file mode 100644
index 0000000000..f3669d2f0f
--- /dev/null
+++ b/apps/web/e2e/tests/task/file-tree-sorting.spec.ts
@@ -0,0 +1,98 @@
+import fs from "node:fs";
+import path from "node:path";
+import { type Page } from "@playwright/test";
+import { test, expect } from "../../fixtures/test-base";
+import type { SeedData } from "../../fixtures/test-base";
+import type { ApiClient } from "../../helpers/api-client";
+import { SessionPage } from "../../pages/session-page";
+
+async function seedSimpleTask(
+  testPage: Page,
+  apiClient: ApiClient,
+  seedData: SeedData,
+  title: string,
+): Promise<SessionPage> {
+  const task = await apiClient.createTaskWithAgent(
+    seedData.workspaceId,
+    title,
+    seedData.agentProfileId,
+    {
+      description: "/e2e:simple-message",
+      workflow_id: seedData.workflowId,
+      workflow_step_id: seedData.startStepId,
+      repository_ids: [seedData.repositoryId],
+    },
+  );
+
+  await testPage.goto(`/t/${task.id}`);
+
+  const session = new SessionPage(testPage);
+  await session.waitForLoad();
+  await expect(session.idleInput()).toBeVisible({ timeout: 30_000 });
+
+  return session;
+}
+
+test.describe("File tree sorting", () => {
+  test.describe.configure({ retries: 1 });
+
+  test("directories appear before files inside nested folders, including dotfiles", async ({
+    testPage,
+    apiClient,
+    seedData,
+    backend,
+  }) => {
+    // Seed a nested folder containing a mix of dirs (incl. a dot-dir) and files
+    // (incl. dotfiles). If the sort is wrong, dotfiles will appear above .vscode.
+    const repoDir = path.join(backend.tmpDir, "repos", "e2e-repo");
+    const subDir = path.join(repoDir, "sub");
+
+    fs.mkdirSync(path.join(subDir, "adir"), { recursive: true });
+    fs.writeFileSync(path.join(subDir, "adir", "keep.txt"), "x\n");
+    fs.mkdirSync(path.join(subDir, ".vscode"), { recursive: true });
+    fs.writeFileSync(path.join(subDir, ".vscode", "settings.json"), "{}\n");
+    fs.writeFileSync(path.join(subDir, ".gitignore"), "node_modules\n");
+    fs.writeFileSync(path.join(subDir, ".golangci.yaml"), "linters:\n");
+    fs.writeFileSync(path.join(subDir, "zfile.txt"), "z\n");
+
+    const session = await seedSimpleTask(testPage, apiClient, seedData, "File Tree Sorting");
+
+    await session.clickTab("Files");
+    await expect(session.files).toBeVisible({ timeout: 5_000 });
+
+    // Expand the sub folder
+    const subRow = session.files.locator('[data-testid="file-tree-node"][data-path="sub"]');
+    await expect(subRow).toBeVisible({ timeout: 10_000 });
+    await subRow.click();
+
+    // Wait until all expected children are rendered
+    const childSelector = (p: string) =>
+      session.files.locator(`[data-testid="file-tree-node"][data-path="${p}"]`);
+
+    await expect(childSelector("sub/adir")).toBeVisible({ timeout: 10_000 });
+    await expect(childSelector("sub/.vscode")).toBeVisible({ timeout: 10_000 });
+    await expect(childSelector("sub/.gitignore")).toBeVisible({ timeout: 10_000 });
+    await expect(childSelector("sub/.golangci.yaml")).toBeVisible({ timeout: 10_000 });
+    await expect(childSelector("sub/zfile.txt")).toBeVisible({ timeout: 10_000 });
+
+    // Read the rendered order of sub's direct children
+    const childPaths = await session.files
+      .locator('[data-testid="file-tree-node"]')
+      .evaluateAll((els) =>
+        els
+          .map((el) => ({
+            path: el.getAttribute("data-path") ?? "",
+            isDir: el.getAttribute("data-is-dir") === "true",
+          }))
+          .filter((n) => n.path.startsWith("sub/") && !n.path.slice("sub/".length).includes("/")),
+      );
+
+    // Directories must come before files. Within each group, order follows
+    // the comparator's localeCompare (dot-prefixed names sort before letters).
+    const dirs = childPaths.filter((n) => n.isDir).map((n) => n.path);
+    const files = childPaths.filter((n) => !n.isDir).map((n) => n.path);
+
+    expect(dirs).toEqual(["sub/.vscode", "sub/adir"]);
+    expect(files).toEqual(["sub/.gitignore", "sub/.golangci.yaml", "sub/zfile.txt"]);
+  });
+});