Mix ground turkey, buttery round cracker crumbs, milk, onion, egg, salt, garlic, and black pepper in a bowl; shape into a loaf and place on the prepared jelly roll pan.
Mix ketchup, brown sugar, and Worcestershire sauce in a separate bowl; set aside.
Bake meatloaf in preheated oven for 30 minutes; remove from oven and drain liquids. Top meatloaf with ketchup topping. Return loaf to oven and continue baking until no longer pink in the center, about 30 minutes more. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).