Preheat the oven to 375 degrees F (190 degrees C). Spray a baking dish with nonstick cooking spray.
Rinse tilapia fillets under cool water, and pat dry with paper towels.
Place fillets in the prepared baking dish. Pour lemon juice over fillets, then drizzle butter on top. Sprinkle with garlic, parsley, and pepper.
Bake in the preheated oven until fish is white and flakes when pulled apart with a fork, about 30 minutes.
