In Window Rock, your best bet is the Quality Inn Navajo Nation Capital, which serves moderately priced American, Mexican, and Navajo food. Try the Navajo tacos or mutton stew. The restaurant is open daily from 6am to 9pm.
At the Ch'ihootso Indian Marketplace (tel. 928/871-5443), at the junction of Ariz. 264 and Navajo Rte. 12, you'll find several tiny restaurants that specialize in traditional Navajo dishes such as mutton stew and fry bread. On weekends a crafts/flea market is in the parking lot here. Hours vary.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.