diff --git a/src/components/favorites/QueryFavorites.tsx b/src/components/favorites/QueryFavorites.tsx
index eb10e9f..7e5233e 100644
--- a/src/components/favorites/QueryFavorites.tsx
+++ b/src/components/favorites/QueryFavorites.tsx
@@ -14,6 +14,7 @@ import { useMemo, useState } from "react";
 import { useContextMenu } from "../../hooks/useContextMenu";
 import { useEditorStore } from "../../stores/editorStore";
 import { type Favorite, useFavoritesStore } from "../../stores/favoritesStore";
+import { ConfirmDialog } from "../common/ConfirmDialog";
 
 export function QueryFavorites() {
   const favorites = useFavoritesStore((s) => s.favorites);
@@ -35,6 +36,9 @@ export function QueryFavorites() {
   const [editDescValue, setEditDescValue] = useState("");
   const [showNewCategory, setShowNewCategory] = useState(false);
   const [newCategoryName, setNewCategoryName] = useState("");
+  const [pendingDelete, setPendingDelete] = useState<{ cat: string; count: number } | null>(
+    null,
+  );
 
   const { contextMenu, showContextMenu } = useContextMenu();
 
@@ -212,7 +216,10 @@ export function QueryFavorites() {
                             label: "Delete Category",
                             icon: <Trash2 className="h-3.5 w-3.5" />,
                             danger: true,
-                            onClick: () => deleteCategory(cat),
+                            onClick: () => {
+                              const count = favorites.filter((f) => f.category === cat).length;
+                              setPendingDelete({ cat, count });
+                            },
                           },
                         ]);
                       }
@@ -365,6 +372,23 @@ export function QueryFavorites() {
           )}
       </div>
       {contextMenu}
+      <ConfirmDialog
+        isOpen={pendingDelete !== null}
+        title={`Delete category "${pendingDelete?.cat ?? ""}"?`}
+        message={pendingDelete
+          ? `${pendingDelete.count} favorite${pendingDelete.count === 1 ? "" : "s"} will be moved to Uncategorized.`
+          : ""}
+        confirmLabel="Delete"
+        cancelLabel="Cancel"
+        danger
+        onConfirm={() => {
+          if (pendingDelete) {
+            deleteCategory(pendingDelete.cat);
+          }
+          setPendingDelete(null);
+        }}
+        onCancel={() => setPendingDelete(null)}
+      />
     </div>
   );
 }
diff --git a/src/components/favorites/__tests__/QueryFavorites.test.tsx b/src/components/favorites/__tests__/QueryFavorites.test.tsx
index f5e0256..d6c79af 100644
--- a/src/components/favorites/__tests__/QueryFavorites.test.tsx
+++ b/src/components/favorites/__tests__/QueryFavorites.test.tsx
@@ -1,16 +1,16 @@
 import { fireEvent, render, screen } from "@testing-library/react";
-import { beforeAll, describe, expect, it, vi } from "vitest";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
 import { QueryFavorites } from "../QueryFavorites";
 
 const { useFavoritesStoreFn } = vi.hoisted(() => {
   return { useFavoritesStoreFn: vi.fn() };
 });
 
-vi.mock("../../stores/favoritesStore", () => ({
+vi.mock("../../../stores/favoritesStore", () => ({
   useFavoritesStore: useFavoritesStoreFn,
 }));
 
-vi.mock("../../stores/editorStore", () => ({
+vi.mock("../../../stores/editorStore", () => ({
   useEditorStore: {
     getState: vi.fn(() => ({
       tabs: [{ id: "tab1", type: "query", content: "" }],
@@ -21,43 +21,96 @@ vi.mock("../../stores/editorStore", () => ({
   },
 }));
 
-vi.mock("../../hooks/useContextMenu", () => ({
-  useContextMenu: vi.fn(() => ({ contextMenu: null, showContextMenu: vi.fn() })),
-}));
+// Context-menu mock that renders the items as buttons so tests can click
+// them. Uses real React state so updates trigger re-renders of the host.
+vi.mock("../../../hooks/useContextMenu", async () => {
+  const { useState, useCallback } = await import("react");
+  return {
+    useContextMenu: () => {
+      const [items, setItems] = useState<
+        { label: string; onClick: () => void; danger?: boolean; separator?: boolean }[]
+      >([]);
+      const showContextMenu = useCallback(
+        (_e: unknown, newItems: typeof items) => {
+          setItems(newItems);
+        },
+        [],
+      );
+      const hideContextMenu = useCallback(() => setItems([]), []);
+      const contextMenu = items.length > 0
+        ? (
+          <div data-testid="ctx-menu">
+            {items.map((item, i) =>
+              item.separator
+                ? <hr key={i} data-testid="ctx-sep" />
+                : (
+                  <button
+                    key={i}
+                    data-testid={`ctx-item-${item.label}`}
+                    data-danger={item.danger ? "true" : undefined}
+                    onClick={item.onClick}
+                  >
+                    {item.label}
+                  </button>
+                )
+            )}
+          </div>
+        )
+        : null;
+      return { contextMenu, showContextMenu, hideContextMenu };
+    },
+  };
+});
+
+const baselineFavorites = [
+  {
+    id: "fav1",
+    name: "Get Active Users",
+    sql: "SELECT * FROM users WHERE active = 1",
+    category: "Uncategorized",
+    description: "Returns all active users",
+    createdAt: "2025-01-01",
+    updatedAt: "2025-01-01",
+  },
+  {
+    id: "fav2",
+    name: "Order Summary",
+    sql: "SELECT COUNT(*) FROM orders",
+    category: "Reports",
+    description: "Daily order count",
+    connectionName: "Prod DB",
+    createdAt: "2025-01-02",
+    updatedAt: "2025-01-02",
+  },
+];
+
+const storeState = {
+  favorites: baselineFavorites,
+  categories: ["Uncategorized", "Reports"],
+  deleteFavorite: vi.fn(),
+  renameFavorite: vi.fn(),
+  moveToCategory: vi.fn(),
+  updateFavorite: vi.fn(),
+  addCategory: vi.fn(),
+  deleteCategory: vi.fn(),
+};
 
 beforeAll(() => {
-  useFavoritesStoreFn.mockImplementation((s: (v: any) => unknown) =>
-    s({
-      favorites: [
-        {
-          id: "fav1",
-          name: "Get Active Users",
-          sql: "SELECT * FROM users WHERE active = 1",
-          category: "Uncategorized",
-          description: "Returns all active users",
-          createdAt: "2025-01-01",
-          updatedAt: "2025-01-01",
-        },
-        {
-          id: "fav2",
-          name: "Order Summary",
-          sql: "SELECT COUNT(*) FROM orders",
-          category: "Reports",
-          description: "Daily order count",
-          connectionName: "Prod DB",
-          createdAt: "2025-01-02",
-          updatedAt: "2025-01-02",
-        },
-      ],
-      categories: ["Uncategorized", "Reports"],
-      deleteFavorite: vi.fn(),
-      renameFavorite: vi.fn(),
-      moveToCategory: vi.fn(),
-      updateFavorite: vi.fn(),
-      addCategory: vi.fn(),
-      deleteCategory: vi.fn(),
-    })
-  );
+  useFavoritesStoreFn.mockImplementation((s: (v: typeof storeState) => unknown) => s(storeState));
+});
+
+beforeEach(() => {
+  storeState.deleteFavorite.mockClear();
+  storeState.renameFavorite.mockClear();
+  storeState.moveToCategory.mockClear();
+  storeState.updateFavorite.mockClear();
+  storeState.addCategory.mockClear();
+  storeState.deleteCategory.mockClear();
+});
+
+afterEach(() => {
+  storeState.favorites = baselineFavorites;
+  storeState.categories = ["Uncategorized", "Reports"];
 });
 
 describe("QueryFavorites", () => {
@@ -76,3 +129,87 @@ describe("QueryFavorites", () => {
     expect(container.querySelector(".flex.h-full.flex-col")).toBeInTheDocument();
   });
 });
+
+// ─────────────────────────────────────────────────────────────────────────
+// Issue #337: confirm before deleting a category that holds favorites.
+// ─────────────────────────────────────────────────────────────────────────
+describe("QueryFavorites — delete category confirmation (#337)", () => {
+  function makeReportsFavorites(count: number) {
+    return Array.from({ length: count }, (_, i) => ({
+      id: `rep-${i}`,
+      name: `Report ${i}`,
+      sql: `SELECT ${i} FROM reports`,
+      category: "Reports",
+      description: undefined as string | undefined,
+      connectionName: undefined as string | undefined,
+      createdAt: "2025-01-01",
+      updatedAt: "2025-01-01",
+    }));
+  }
+
+  it("shows a ConfirmDialog with category name and favorite count when Delete Category is clicked", () => {
+    storeState.favorites = makeReportsFavorites(50);
+    storeState.categories = ["Uncategorized", "Reports"];
+
+    render(<QueryFavorites />);
+
+    const reportsHeader = screen.getByText("Reports").closest("button");
+    expect(reportsHeader).not.toBeNull();
+    fireEvent.contextMenu(reportsHeader!);
+
+    const deleteBtn = screen.getByTestId("ctx-item-Delete Category");
+    expect(deleteBtn).toBeInTheDocument();
+    fireEvent.click(deleteBtn);
+
+    // ConfirmDialog renders the category name, plural favorite count, and target category.
+    expect(screen.getByText("Delete category \"Reports\"?")).toBeInTheDocument();
+    expect(screen.getByText("50 favorites will be moved to Uncategorized.")).toBeInTheDocument();
+
+    // Store action has NOT fired yet — user has not confirmed.
+    expect(storeState.deleteCategory).not.toHaveBeenCalled();
+  });
+
+  it("calls deleteCategory when the user confirms the dialog", () => {
+    storeState.favorites = makeReportsFavorites(50);
+    storeState.categories = ["Uncategorized", "Reports"];
+
+    render(<QueryFavorites />);
+    fireEvent.contextMenu(screen.getByText("Reports").closest("button")!);
+    fireEvent.click(screen.getByTestId("ctx-item-Delete Category"));
+
+    // "Delete" is the confirmLabel set by QueryFavorites for danger flows.
+    fireEvent.click(screen.getByRole("button", { name: /^delete$/i }));
+
+    expect(storeState.deleteCategory).toHaveBeenCalledTimes(1);
+    expect(storeState.deleteCategory).toHaveBeenCalledWith("Reports");
+
+    expect(screen.queryByText("Delete category \"Reports\"?")).not.toBeInTheDocument();
+  });
+
+  it("does NOT call deleteCategory when the user cancels", () => {
+    storeState.favorites = makeReportsFavorites(50);
+    storeState.categories = ["Uncategorized", "Reports"];
+
+    render(<QueryFavorites />);
+    fireEvent.contextMenu(screen.getByText("Reports").closest("button")!);
+    fireEvent.click(screen.getByTestId("ctx-item-Delete Category"));
+
+    fireEvent.click(screen.getByRole("button", { name: /^cancel$/i }));
+
+    expect(storeState.deleteCategory).not.toHaveBeenCalled();
+
+    expect(screen.queryByText("Delete category \"Reports\"?")).not.toBeInTheDocument();
+    expect(screen.getByText("Reports")).toBeInTheDocument();
+  });
+
+  it("uses the singular 'favorite' when the category has exactly one entry", () => {
+    storeState.favorites = makeReportsFavorites(1);
+    storeState.categories = ["Uncategorized", "Reports"];
+
+    render(<QueryFavorites />);
+    fireEvent.contextMenu(screen.getByText("Reports").closest("button")!);
+    fireEvent.click(screen.getByTestId("ctx-item-Delete Category"));
+
+    expect(screen.getByText("1 favorite will be moved to Uncategorized.")).toBeInTheDocument();
+  });
+});