Mix olive oil, soy sauce, lemon juice, Worcestershire, garlic, oregano, paprika, salt, and pepper in a big bowl until well combined.
Add the steak cubes and toss so they’re coated all over, then cover and stick in the fridge for at least 1 hour (2 hours is even better).
While the steak marinates, soak your wooden skewers in water for about 30 minutes if you're using them—this keeps them from burning.
Thread the steak, peppers, onions, and mushrooms onto the skewers, alternating meat and veggies for even cooking.
Heat your grill to medium-high and oil the grates lightly.
Grill the kabobs for 10-12 minutes, turning every few minutes so the steak gets a good char and cooks to your liking.
Let the kabobs rest for about 5 minutes after grilling so the juices stay put.