diff --git a/src/app/api/owner-expenses/__tests__/route.test.ts b/src/app/api/owner-expenses/__tests__/route.test.ts
index c7fa9f8f..6e601185 100644
--- a/src/app/api/owner-expenses/__tests__/route.test.ts
+++ b/src/app/api/owner-expenses/__tests__/route.test.ts
@@ -4,6 +4,7 @@ import { NextRequest } from "next/server";
 const mocks = vi.hoisted(() => ({
   findMany: vi.fn(),
   create: vi.fn(),
+  deleteMany: vi.fn(),
 }));
 
 vi.mock("@/lib/prisma", () => ({
@@ -11,18 +12,22 @@ vi.mock("@/lib/prisma", () => ({
     externalUsageEvent: {
       findMany: mocks.findMany,
       create: mocks.create,
+      deleteMany: mocks.deleteMany,
     },
   },
 }));
 
 let GET: typeof import("../route").GET;
 let POST: typeof import("../route").POST;
+let DELETE: typeof import("../route").DELETE;
+let createSessionToken: typeof import("@/lib/auth").createSessionToken;
 
 const READ_TOKEN = "r".repeat(64);
 
 beforeAll(async () => {
   process.env.SESSION_SECRET = "s".repeat(64);
-  ({ GET, POST } = await import("../route"));
+  ({ GET, POST, DELETE } = await import("../route"));
+  ({ createSessionToken } = await import("@/lib/auth"));
 });
 
 beforeEach(() => {
@@ -32,6 +37,8 @@ beforeEach(() => {
   delete process.env.OWNER_EXPENSE_TOKEN;
   mocks.findMany.mockReset();
   mocks.findMany.mockResolvedValue([]);
+  mocks.deleteMany.mockReset();
+  mocks.deleteMany.mockResolvedValue({ count: 0 });
 });
 
 function getRequest(
@@ -155,3 +162,107 @@ describe("GET /api/owner-expenses", () => {
     }
   });
 });
+
+describe("DELETE /api/owner-expenses", () => {
+  const KEY_A = `owner-recorded-expense:v1:${"a".repeat(64)}`;
+  const KEY_B = `owner-recorded-expense:v1:${"b".repeat(64)}`;
+
+  function deleteRequest(
+    keys: unknown,
+    headers: Record<string, string> = {}
+  ): NextRequest {
+    const token = createSessionToken();
+    return new NextRequest("https://usage.jays.services/api/owner-expenses", {
+      method: "DELETE",
+      headers: {
+        "content-type": "application/json",
+        cookie: `dashboard_session=${token}`,
+        ...headers,
+      },
+      body: JSON.stringify({ idempotencyKeys: keys }),
+    });
+  }
+
+  it("401s without a session cookie", async () => {
+    const request = new NextRequest(
+      "https://usage.jays.services/api/owner-expenses",
+      {
+        method: "DELETE",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ idempotencyKeys: [KEY_A] }),
+      }
+    );
+    const response = await DELETE(request);
+    expect(response.status).toBe(401);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("401s with an owner expense token but no session (no token fallback)", async () => {
+    process.env.OWNER_EXPENSE_TOKEN = "t".repeat(64);
+    const request = new NextRequest(
+      "https://usage.jays.services/api/owner-expenses",
+      {
+        method: "DELETE",
+        headers: {
+          "content-type": "application/json",
+          "x-owner-expense-token": "t".repeat(64),
+        },
+        body: JSON.stringify({ idempotencyKeys: [KEY_A] }),
+      }
+    );
+    const response = await DELETE(request);
+    expect(response.status).toBe(401);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("403s a cross-site cookie request (CSRF guard)", async () => {
+    const response = await DELETE(
+      deleteRequest([KEY_A], { "sec-fetch-site": "cross-site" })
+    );
+    expect(response.status).toBe(403);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("400s on a malformed idempotency key", async () => {
+    const response = await DELETE(deleteRequest(["not-a-key"]));
+    expect(response.status).toBe(400);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("400s on an empty key list", async () => {
+    const response = await DELETE(deleteRequest([]));
+    expect(response.status).toBe(400);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("400s on a non-expense key shape", async () => {
+    const response = await DELETE(deleteRequest(["usage-telemetry:v1:abc"]));
+    expect(response.status).toBe(400);
+    expect(mocks.deleteMany).not.toHaveBeenCalled();
+  });
+
+  it("deletes scoped to owner-recorded expenses and reports notFound", async () => {
+    mocks.findMany.mockResolvedValue([{ idempotencyKey: KEY_A }]);
+    mocks.deleteMany.mockResolvedValue({ count: 1 });
+    const response = await DELETE(deleteRequest([KEY_A, KEY_B]));
+    expect(response.status).toBe(200);
+    const body = await response.json();
+    expect(body).toEqual({
+      requested: 2,
+      deleted: 1,
+      notFound: [KEY_B],
+    });
+    expect(mocks.deleteMany).toHaveBeenCalledTimes(1);
+    const where = mocks.deleteMany.mock.calls[0][0].where;
+    expect(where.sourceApp).toBe("owner-recorded-expense");
+    expect(where.idempotencyKey).toEqual({ in: [KEY_A, KEY_B] });
+  });
+
+  it("dedupes repeated keys", async () => {
+    mocks.findMany.mockResolvedValue([{ idempotencyKey: KEY_A }]);
+    mocks.deleteMany.mockResolvedValue({ count: 1 });
+    const response = await DELETE(deleteRequest([KEY_A, KEY_A]));
+    const body = await response.json();
+    expect(body.requested).toBe(1);
+  });
+});
diff --git a/src/app/api/owner-expenses/route.ts b/src/app/api/owner-expenses/route.ts
index 5c90c3fc..bc152e4a 100644
--- a/src/app/api/owner-expenses/route.ts
+++ b/src/app/api/owner-expenses/route.ts
@@ -1,5 +1,9 @@
 import { NextRequest, NextResponse } from "next/server";
-import { hasValidDashboardSession, shouldEnforceDashboardSession } from "@/lib/auth";
+import {
+  hasValidDashboardSession,
+  isCsrfSafeRequest,
+  shouldEnforceDashboardSession,
+} from "@/lib/auth";
 import { readBoundedJsonBody } from "@/lib/bounded-request-body";
 import {
   isUsageReadAuthorized,
@@ -150,3 +154,86 @@ export async function GET(request: NextRequest) {
     hasMore,
   });
 }
+
+const DELETE_MAX_KEYS = 100;
+const OWNER_EXPENSE_KEY_RE = /^owner-recorded-expense:v1:[0-9a-f]{64}$/;
+
+/**
+ * DELETE /api/owner-expenses
+ *
+ * Admin-only removal of owner-recorded expense rows by idempotency key.
+ * Dashboard session cookie required — there is intentionally no
+ * OWNER_EXPENSE_TOKEN fallback; deleting ledger rows is destructive and
+ * stays behind the admin session.  The CSRF guard applies because this is
+ * a cookie-authenticated mutator.
+ *
+ * Two independent safety pins keep a key from ever deleting a non-expense
+ * row: the key format is validated against the owner-expense idempotency
+ * shape, and the delete WHERE clause is pinned to
+ * sourceApp "owner-recorded-expense".
+ *
+ * Body: { "idempotencyKeys": ["owner-recorded-expense:v1:<64hex>", ...] }
+ * Response: { requested, deleted, notFound: [...] }
+ */
+export async function DELETE(request: NextRequest) {
+  if (!hasValidDashboardSession(request)) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  if (!isCsrfSafeRequest(request)) {
+    return NextResponse.json({ error: "Forbidden" }, { status: 403 });
+  }
+
+  let body: unknown;
+  try {
+    body = await readBoundedJsonBody(request, {
+      label: "Owner expense delete body",
+    });
+  } catch (error) {
+    const message = error instanceof Error ? error.message : "Invalid request";
+    return NextResponse.json({ error: message }, { status: 400 });
+  }
+
+  const rawKeys =
+    body && typeof body === "object"
+      ? (body as Record<string, unknown>).idempotencyKeys
+      : undefined;
+  if (
+    !Array.isArray(rawKeys) ||
+    rawKeys.length === 0 ||
+    rawKeys.length > DELETE_MAX_KEYS ||
+    rawKeys.some(
+      (key) => typeof key !== "string" || !OWNER_EXPENSE_KEY_RE.test(key)
+    )
+  ) {
+    return NextResponse.json(
+      {
+        error:
+          "idempotencyKeys must be a non-empty array of at most 100 owner-recorded-expense idempotency keys",
+      },
+      { status: 400 }
+    );
+  }
+  const keys = [...new Set(rawKeys as string[])];
+
+  const existing = await prisma.externalUsageEvent.findMany({
+    where: {
+      sourceApp: OWNER_EXPENSE_SOURCE_APP,
+      idempotencyKey: { in: keys },
+    },
+    select: { idempotencyKey: true },
+  });
+  const existingKeys = new Set(existing.map((row) => row.idempotencyKey));
+
+  const deleted = await prisma.externalUsageEvent.deleteMany({
+    where: {
+      sourceApp: OWNER_EXPENSE_SOURCE_APP,
+      idempotencyKey: { in: keys },
+    },
+  });
+
+  return NextResponse.json({
+    requested: keys.length,
+    deleted: deleted.count,
+    notFound: keys.filter((key) => !existingKeys.has(key)),
+  });
+}