diff --git a/.changeset/fix-no-unstable-deps-prototype-lookup.md b/.changeset/fix-no-unstable-deps-prototype-lookup.md
new file mode 100644
index 00000000000..2ed2fbd308f
--- /dev/null
+++ b/.changeset/fix-no-unstable-deps-prototype-lookup.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/eslint-plugin-query': patch
+---
+
+Fix false positive in `no-unstable-deps` when a variable is assigned from a call whose name matches an `Object.prototype` method (e.g. `toString`, `valueOf`, `constructor`).
diff --git a/packages/eslint-plugin-query/src/__tests__/no-unstable-deps.test.ts b/packages/eslint-plugin-query/src/__tests__/no-unstable-deps.test.ts
index fca18c41cd2..141cf450d7b 100644
--- a/packages/eslint-plugin-query/src/__tests__/no-unstable-deps.test.ts
+++ b/packages/eslint-plugin-query/src/__tests__/no-unstable-deps.test.ts
@@ -405,3 +405,29 @@ reactHookNames.forEach((reactHookName) => {
     },
   )
 })
+
+const protoMethodNames = [
+  'toString',
+  'valueOf',
+  'constructor',
+  'hasOwnProperty',
+  'isPrototypeOf',
+  'propertyIsEnumerable',
+  'toLocaleString',
+] as const
+
+ruleTester.run('no-unstable-deps', rule, {
+  valid: protoMethodNames.map((method) => ({
+    name: `should not flag variable from "${method}()" call as unstable dep`,
+    code: `
+      import { useCallback } from "React";
+
+      function Component() {
+        const result = ${method}();
+        const cb = useCallback(() => { result }, [result]);
+        return null;
+      }
+    `,
+  })),
+  invalid: [],
+})
diff --git a/packages/eslint-plugin-query/src/rules/no-unstable-deps/no-unstable-deps.rule.ts b/packages/eslint-plugin-query/src/rules/no-unstable-deps/no-unstable-deps.rule.ts
index 934773faa0f..edb2732ee28 100644
--- a/packages/eslint-plugin-query/src/rules/no-unstable-deps/no-unstable-deps.rule.ts
+++ b/packages/eslint-plugin-query/src/rules/no-unstable-deps/no-unstable-deps.rule.ts
@@ -139,7 +139,10 @@ export const rule = createRule({
       }
 
       if (callExpression.callee.type === AST_NODE_TYPES.Identifier) {
-        return trackedCustomHooks[callExpression.callee.name]
+        const calleeName = callExpression.callee.name
+        return Object.hasOwn(trackedCustomHooks, calleeName)
+          ? trackedCustomHooks[calleeName]
+          : undefined
       }
 
       return undefined