Cook ground turkey in a skillet over medium heat, breaking it up with a fork as it cooks.
Cook just until it loses its pink color. Drain off any fat. Add cooked turkey to the slow cooker.
Add broken spaghetti and marinara. Stir to combine all ingredients, ensuring spaghetti is coated with marinara. Cover and cook on low 2-3 hours or until spaghetti is al dente.