Lay tilapia filets into a lightly greased 9x13 baking dish. Preheat oven to 400 degrees.
In a small bowl, whisk together lemon juice, melted butter, and garlic. Pour over tilapia. Season with salt and pepper. Tuck lemon slices in (optional).
Bake at 400 degrees for 10-12 minutes, until fish flakes easily with a fork.
Serve hot with additional lemon wedges and garnish with parsley.