Preheat oven to 375°F (190°C).
In a large skillet, cook the ground turkey over medium heat until browned. Add the onion and garlic and cook for another 2-3 minutes.
Stir in the crushed tomatoes, oregano, basil, salt, and pepper. Simmer for 10 minutes.
In a separate skillet, sauté the spinach until wilted.
Place a layer of zucchini slices in the bottom of a greased baking dish. Top with half of the turkey mixture, followed by half of the spinach and feta cheese. Repeat the layers.
Sprinkle the top with mozzarella cheese.
Bake for 30-35 minutes, or until the cheese is melted and bubbly.
Let the lasagna cool for 10 minutes before serving. Enjoy!