In a large bowl, combine ground turkey, breadcrumbs, Parmesan cheese, egg, minced garlic, chopped onion, parsley, oregano, salt, and black pepper. Mix gently until just combined.
Form the mixture into 16 meatballs, about 1 inch in diameter.
Heat olive oil in a large skillet over medium heat. Add the meatballs in batches, cooking for 5-6 minutes, turning occasionally, until browned on all sides. Remove meatballs and set aside.
Pour marinara sauce into the same skillet and bring to a simmer over medium heat.
Return the meatballs to the skillet, cover, and simmer for 15 minutes until cooked through.
While the meatballs cook, bring a large pot of salted water to a boil. Add spaghetti and cook according to package instructions until al dente. Drain and set aside.
Divide the spaghetti among four plates. Top with turkey meatballs and spoon sauce over the top.
Garnish with chopped fresh basil and serve immediately.