In a spacious bowl, combine olive oil, minced garlic, lemon juice, salt, and pepper to create a flavorful marinade. Add the steak and shrimp into the bowl, ensuring each piece is well-coated. Cover with plastic wrap and let them marinate for at least 30 minutes, or up to 2 hours in the refrigerator.

While the steak and shrimp are absorbing the marinade, wash and chop the bell peppers, red onion, and zucchini into kabob-friendly pieces—about 1 to 2 inches in size.

Take metal or soaked wooden skewers, and thread the marinated steak, shrimp, and vegetables onto them, alternating each ingredient for visual appeal.

Preheat your grill to medium-high heat (around 400°F), and oil the grill grates to prevent sticking.

Carefully place the assembled kabobs on the preheated grill. Cook for 10-15 minutes, turning them occasionally for even cooking.

Once grilled to perfection, remove the kabobs from the grill and let them rest for a few minutes before serving with extra lemon wedges.