Preheat the oven to 350 degrees F (175 degrees C). Line a baking sheet with aluminum foil and spray with nonstick cooking spray.
Combine ground turkey, bread crumbs, egg, onion, garlic, salt, and pepper until well mixed. Form into sixteen 1 1/2-inch balls.
Wrap each meatball with a piece of bacon, securing with a toothpick. Brush each bacon-wrapped meatball with teriyaki sauce, then place seam side down on the prepared baking sheet.
Bake in the preheated oven for 15 minutes. Brush meatball with additional teriyaki sauce. Continue baking until the turkey is cooked completely and the bacon has reached your desired crispness, 15 to 20 minutes more.