Prepare the Marinade: In a medium bowl, combine the olive oil, soy sauce, Worcestershire sauce, minced garlic, dried oregano, paprika, salt, and pepper. Whisk well to blend.
Marinate the Steak: Place the steak cubes in a resealable plastic bag or shallow dish. Pour the marinade over the steak, ensuring each piece is evenly coated. Seal the bag or cover the dish and refrigerate for at least 30 minutes (or up to 2 hours for more flavor).
Prepare the Vegetables: While the steak marinates, prepare the vegetables. Cut the bell peppers, onion, and zucchini into pieces that will fit well on the skewers.
Assemble the Kabobs: Thread the marinated steak cubes and vegetables onto the skewers, alternating between steak and vegetables.
Grill the Kabobs: Preheat the grill to medium-high heat. Place the skewers on the grill and cook for 6-8 minutes, turning occasionally, until the steak reaches your desired level of doneness (medium-rare to medium is typically about 4-5 minutes per side).
Serve: Remove the kabobs from the grill and let them rest for a few minutes. Serve hot with your favorite side dishes and enjoy!