In a large bowl, mix together the ground turkey, bread crumbs, onion, egg, garlic powder, salt, and pepper. Form the mixture into 1 1/2 inch meatballs.
Arrange the meatballs in an ungreased 9x13 inch baking dish.
In a medium bowl, whisk together the ketchup, brown sugar, Worcestershire sauce, vinegar, and soy sauce. Pour the mixture over the meatballs and stir to coat.
Bake in the preheated oven for 20 minutes, or until the meatballs are cooked through.
Interesting Facts
The sweet and sour sauce can be made ahead of time and stored in the refrigerator for up to 1 week.
Ground turkey is a leaner alternative to ground beef.
You can also fry the meatballs in a pan for a crispier texture.