diff --git a/apps/web/components/task/changes-panel-timeline-grouping.test.tsx b/apps/web/components/task/changes-panel-timeline-grouping.test.tsx
new file mode 100644
index 0000000000..2345693499
--- /dev/null
+++ b/apps/web/components/task/changes-panel-timeline-grouping.test.tsx
@@ -0,0 +1,105 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { render, screen, cleanup } from "@testing-library/react";
+import type { ComponentProps } from "react";
+
+vi.mock("./changes-panel-file-row", () => ({
+  FileRow: ({ file }: { file: { path: string } }) => (
+    <li data-testid="file-row">{file.path}</li>
+  ),
+  BulkActionBar: () => null,
+  DefaultActionButtons: () => null,
+}));
+
+vi.mock("./commit-row", () => ({
+  CommitRow: () => null,
+}));
+
+vi.mock("@/hooks/use-multi-select", () => ({
+  useMultiSelect: () => ({
+    selectedPaths: new Set<string>(),
+    isSelected: () => false,
+    handleClick: vi.fn(),
+    clearSelection: vi.fn(),
+  }),
+}));
+
+import { FileListSection } from "./changes-panel-timeline";
+
+afterEach(cleanup);
+
+type Props = ComponentProps<typeof FileListSection>;
+
+const baseProps: Omit<Props, "files" | "variant" | "isLast" | "actionLabel" | "onAction"> = {
+  pendingStageFiles: new Set(),
+  onOpenDiff: vi.fn(),
+  onEditFile: vi.fn(),
+  onStage: vi.fn(),
+  onUnstage: vi.fn(),
+  onDiscard: vi.fn(),
+};
+
+function file(path: string, repo?: string): Props["files"][number] {
+  return {
+    path,
+    status: "modified",
+    staged: false,
+    plus: 1,
+    minus: 0,
+    oldPath: undefined,
+    repositoryName: repo,
+  };
+}
+
+describe("FileListSection — multi-repo grouping", () => {
+  it("renders no repo header when files lack a repository_name (single-repo)", () => {
+    render(
+      <FileListSection
+        {...baseProps}
+        variant="unstaged"
+        isLast={false}
+        actionLabel="Stage all"
+        onAction={() => undefined}
+        files={[file("a.ts"), file("b.ts")]}
+      />,
+    );
+    expect(screen.queryAllByTestId("changes-repo-header")).toHaveLength(0);
+    expect(screen.getAllByTestId("file-row")).toHaveLength(2);
+  });
+
+  it("renders one header per repo when 2+ repos are present", () => {
+    render(
+      <FileListSection
+        {...baseProps}
+        variant="unstaged"
+        isLast={false}
+        actionLabel="Stage all"
+        onAction={() => undefined}
+        files={[
+          file("src/app.tsx", "frontend"),
+          file("src/api.ts", "frontend"),
+          file("handlers/task.go", "backend"),
+        ]}
+      />,
+    );
+    const headers = screen.getAllByTestId("changes-repo-header");
+    expect(headers).toHaveLength(2);
+    expect(headers[0].textContent).toContain("frontend");
+    expect(headers[0].textContent).toContain("2");
+    expect(headers[1].textContent).toContain("backend");
+    expect(headers[1].textContent).toContain("1");
+  });
+
+  it("shows a header for a single named repo too", () => {
+    render(
+      <FileListSection
+        {...baseProps}
+        variant="unstaged"
+        isLast={false}
+        actionLabel="Stage all"
+        onAction={() => undefined}
+        files={[file("a.ts", "only-repo")]}
+      />,
+    );
+    expect(screen.getByTestId("changes-repo-header").textContent).toContain("only-repo");
+  });
+});
diff --git a/apps/web/components/task/changes-panel-timeline.tsx b/apps/web/components/task/changes-panel-timeline.tsx
index 1414ed280f..3e69d5ebae 100644
--- a/apps/web/components/task/changes-panel-timeline.tsx
+++ b/apps/web/components/task/changes-panel-timeline.tsx
@@ -34,8 +34,32 @@ type ChangedFile = {
   plus: number | undefined;
   minus: number | undefined;
   oldPath: string | undefined;
+  /** Repository this file belongs to in multi-repo workspaces; empty for single-repo. */
+  repositoryName?: string;
 };
 
+/**
+ * Groups changed files by repository name, preserving original order within
+ * each group. Returns an empty-name leading group when files lack a
+ * repository name (single-repo workspaces) so the renderer can skip the
+ * per-repo header in that case.
+ */
+function groupChangedFilesByRepository(
+  files: ChangedFile[],
+): Array<{ repositoryName: string; files: ChangedFile[] }> {
+  const order: string[] = [];
+  const buckets = new Map<string, ChangedFile[]>();
+  for (const file of files) {
+    const name = file.repositoryName ?? "";
+    if (!buckets.has(name)) {
+      buckets.set(name, []);
+      order.push(name);
+    }
+    buckets.get(name)!.push(file);
+  }
+  return order.map((name) => ({ repositoryName: name, files: buckets.get(name)! }));
+}
+
 // --- Timeline section dot colors ---
 const DOT_COLORS = {
   unstaged: "bg-yellow-500",
@@ -297,6 +321,80 @@ type FileListSectionProps = {
   onBulkDiscard?: (paths: string[]) => void;
 };
 
+/**
+ * Renders the body of a file-list section. For multi-repo workspaces it
+ * groups files by repository under per-repo subheaders; single-repo
+ * workspaces fall back to a flat list (no header) so the existing UI is
+ * unchanged.
+ */
+function FileListBody(props: {
+  variant: "unstaged" | "staged";
+  files: ChangedFile[];
+  pendingStageFiles: Set<string>;
+  multiSelect: ReturnType<typeof useMultiSelect>;
+  onKeyDown: (e: React.KeyboardEvent) => void;
+  onOpenDiff: (path: string) => void;
+  onEditFile: (path: string) => void;
+  onStage: (path: string) => void;
+  onUnstage: (path: string) => void;
+  onDiscard: (path: string) => void;
+}) {
+  const { variant, files, pendingStageFiles, multiSelect } = props;
+  const groups = useMemo(() => groupChangedFilesByRepository(files), [files]);
+  const showRepoHeaders = groups.length > 1 || (groups[0]?.repositoryName ?? "") !== "";
+
+  const renderRow = (file: ChangedFile) => (
+    <FileRow
+      key={`${file.repositoryName ?? ""}:${file.path}`}
+      file={file}
+      isPending={pendingStageFiles.has(file.path)}
+      isSelected={multiSelect.isSelected(file.path)}
+      onSelect={multiSelect.handleClick}
+      onOpenDiff={props.onOpenDiff}
+      onStage={props.onStage}
+      onUnstage={props.onUnstage}
+      onDiscard={props.onDiscard}
+      onEditFile={props.onEditFile}
+    />
+  );
+
+  return (
+    <div>
+      <ul
+        data-testid={`${variant}-file-list`}
+        className="space-y-0.5"
+        tabIndex={-1}
+        onKeyDown={props.onKeyDown}
+      >
+        {groups.map((group) =>
+          showRepoHeaders ? (
+            <li
+              key={group.repositoryName || "__no_repo__"}
+              data-testid="changes-repo-group"
+              data-repository-name={group.repositoryName || ""}
+            >
+              <div
+                className="flex items-center gap-1.5 px-1 py-0.5 text-[11px] font-medium text-muted-foreground/80 uppercase tracking-wide"
+                data-testid="changes-repo-header"
+              >
+                <span className="truncate">{group.repositoryName || "Other"}</span>
+                <span className="text-muted-foreground/50 normal-case tracking-normal">
+                  {group.files.length}
+                </span>
+              </div>
+              <ul className="space-y-0.5">{group.files.map(renderRow)}</ul>
+            </li>
+          ) : (
+            // Single-repo flat list: render rows inline so the DOM shape stays
+            // identical to the pre-multi-repo behavior.
+            group.files.map(renderRow)
+          ),
+        )}
+      </ul>
+    </div>
+  );
+}
+
 export function FileListSection(props: FileListSectionProps) {
   const {
     variant,
@@ -332,29 +430,18 @@ export function FileListSection(props: FileListSectionProps) {
       data-testid={`${variant}-files-section`}
     >
       {files.length > 0 && (
-        <div>
-          <ul
-            data-testid={`${variant}-file-list`}
-            className="space-y-0.5"
-            tabIndex={-1}
-            onKeyDown={handleKeyDown}
-          >
-            {files.map((file) => (
-              <FileRow
-                key={file.path}
-                file={file}
-                isPending={pendingStageFiles.has(file.path)}
-                isSelected={multiSelect.isSelected(file.path)}
-                onSelect={multiSelect.handleClick}
-                onOpenDiff={onOpenDiff}
-                onStage={onStage}
-                onUnstage={onUnstage}
-                onDiscard={onDiscard}
-                onEditFile={onEditFile}
-              />
-            ))}
-          </ul>
-        </div>
+        <FileListBody
+          variant={variant}
+          files={files}
+          pendingStageFiles={pendingStageFiles}
+          multiSelect={multiSelect}
+          onKeyDown={handleKeyDown}
+          onOpenDiff={onOpenDiff}
+          onStage={onStage}
+          onUnstage={onUnstage}
+          onDiscard={onDiscard}
+          onEditFile={onEditFile}
+        />
       )}
       {files.length > 0 && (
         <div className="mt-1.5 flex items-center gap-1.5">
diff --git a/apps/web/components/task/changes-panel.tsx b/apps/web/components/task/changes-panel.tsx
index c31344b422..23f0f11795 100644
--- a/apps/web/components/task/changes-panel.tsx
+++ b/apps/web/components/task/changes-panel.tsx
@@ -43,6 +43,8 @@ type ChangedFile = {
   plus: number | undefined;
   minus: number | undefined;
   oldPath: string | undefined;
+  /** Repository this file belongs to in multi-repo workspaces; empty for single-repo. */
+  repositoryName?: string;
 };
 
 function mapToChangedFiles(files: FileInfo[]): ChangedFile[] {
@@ -53,6 +55,7 @@ function mapToChangedFiles(files: FileInfo[]): ChangedFile[] {
     plus: file.additions,
     minus: file.deletions,
     oldPath: file.old_path,
+    repositoryName: file.repository_name,
   }));
 }
 
diff --git a/apps/web/hooks/domains/session/use-session-git.ts b/apps/web/hooks/domains/session/use-session-git.ts
index ff65b2d747..688a8ea095 100644
--- a/apps/web/hooks/domains/session/use-session-git.ts
+++ b/apps/web/hooks/domains/session/use-session-git.ts
@@ -1,7 +1,7 @@
 "use client";
 
 import { useState, useCallback, useEffect, useMemo } from "react";
-import { useSessionGitStatus } from "./use-session-git-status";
+import { useSessionGitStatus, useSessionGitStatusByRepo } from "./use-session-git-status";
 import { useSessionCommits } from "./use-session-commits";
 import { useCumulativeDiff } from "./use-cumulative-diff";
 import { useGitOperations } from "@/hooks/use-git-operations";
@@ -72,18 +72,44 @@ export type SessionGit = {
   ) => Promise<PRCreateResult>;
 };
 
+/**
+ * Builds the SessionGit's flat file list. For multi-repo workspaces it
+ * stamps each FileInfo with its repository_name so consumers can group;
+ * for single-repo it returns the legacy single-status files unchanged.
+ */
+function aggregateFilesAcrossRepos(
+  statusByRepo: ReturnType<typeof useSessionGitStatusByRepo>,
+  gitStatus: ReturnType<typeof useSessionGitStatus>,
+): FileInfo[] {
+  if (statusByRepo.length > 0) {
+    const out: FileInfo[] = [];
+    for (const { repository_name, status } of statusByRepo) {
+      if (!status?.files) continue;
+      for (const f of Object.values(status.files)) {
+        out.push(repository_name ? { ...f, repository_name } : f);
+      }
+    }
+    return out;
+  }
+  return gitStatus?.files ? Object.values(gitStatus.files) : [];
+}
+
 export function useSessionGit(sessionId: string | null | undefined): SessionGit {
   const sid = sessionId ?? null;
   const gitStatus = useSessionGitStatus(sid);
+  const statusByRepo = useSessionGitStatusByRepo(sid);
   const { commits, loading: commitsLoading } = useSessionCommits(sid);
   const { diff: cumulativeDiff } = useCumulativeDiff(sid);
   const gitOps = useGitOperations(sid);
 
   const [pendingStageFiles, setPendingStageFiles] = useState<Set<string>>(new Set());
 
+  // Multi-repo: aggregate files from every repo's per-repo status, stamping
+  // each FileInfo with its repository_name so downstream UI can group them.
+  // Single-repo (or repo-less) sessions fall back to the legacy single status.
   const allFiles = useMemo<FileInfo[]>(
-    () => (gitStatus?.files ? Object.values(gitStatus.files) : []),
-    [gitStatus],
+    () => aggregateFilesAcrossRepos(statusByRepo, gitStatus),
+    [statusByRepo, gitStatus],
   );
   const unstagedFiles = useMemo(() => allFiles.filter((f) => !f.staged), [allFiles]);
   const stagedFiles = useMemo(() => allFiles.filter((f) => f.staged), [allFiles]);
diff --git a/apps/web/lib/state/slices/session-runtime/types.ts b/apps/web/lib/state/slices/session-runtime/types.ts
index 02da3f89e9..b24531aeed 100644
--- a/apps/web/lib/state/slices/session-runtime/types.ts
+++ b/apps/web/lib/state/slices/session-runtime/types.ts
@@ -49,6 +49,13 @@ export type FileInfo = {
   old_path?: string;
   diff?: string;
   diff_skip_reason?: "too_large" | "binary" | "truncated" | "budget_exceeded";
+  /**
+   * Repository this file belongs to in multi-repo task workspaces. Stamped
+   * by useSessionGit when aggregating per-repo statuses; empty for single-
+   * repo workspaces. The Changes panel uses it to group files under
+   * per-repository headers.
+   */
+  repository_name?: string;
 };
 
 export type GitStatusEntry = {