Chop all vegetables into bite-sized pieces and set aside.

Heat olive oil in a large skillet over medium-high heat until shimmering.

Add ground beef to the skillet and cook until browned (about 5 minutes). Drain excess fat if necessary.

Add the bell peppers, zucchini, red onion, cherry tomatoes, and minced garlic. Stir-fry for an additional 5 minutes until veggies are tender but crisp.

Season with oregano, salt, and pepper to taste. Squeeze lemon juice over the stir fry just before serving.

Serve hot over rice or couscous or in lettuce wraps.