In a large zipper-topped plastic bag, combine soy sauce, ketchup, ginger and garlic; add turkey strips, seal bag and turn several times to coat; marinate for about 15 minutes (prep the veggies in the meantime).
Heat half of the oil in a skillet or wok over medium-high heat; add green onions and bell peppers and stir-fry until tender-crisp; remove from skillet and keep warm.
Heat remaining oil in the skillet or wok; add turkey strips and marinade; stir-fry for 4 to 5 minutes or until no longer pink in the center.
Return green onion/bell pepper mixture to the skillet or wok; toss and heat through.