Preheat oven to 350 degrees and spray a 9x13-baking dish lightly with non-stick cooking spray.
In a large bowl combine cream of mushroom soup, milk, Worcestershire sauce, garlic salt, and pepper.
Stir in green beans. Spoon half of the bean mixture into prepared baking dish and sprinkle with half of the French fried onions, top with remaining green bean mixture.
Bake for 35 minutes, uncovered. Add the remaining onions to the top of the beans and bake an additional 5 minutes. Remove from oven and serve.