In a small bowl, whisk together the teriyaki sauce and garlic.
Lightly spray a baking pan with cooking spray. Place the grouper fillets in the pan. Brush the teriyaki marinade on both sides of the fillets. Cover and refrigerate for at least 15 minutes to marinate the fish.
Heat the broiler or grill. Position the rack 4 inches from the heat source.
Broil or grill until the fish is not transparent, also called opaque, throughout when tested with a tip of a knife, about 5 to 10 minutes. Remove from the broiler or grill.
Squeeze 1 lemon wedge over each fillet. Then sprinkle with Italian seasoning.
Serve right away.