Combine marinade ingredients in a large bowl.
Place steak cubes into the marinade and stir to coat completely. Refrigerate for at least 1 hour or overnight.
Preheat your grill to medium-high heat.
Skewer the steak, bell peppers and onion onto metal skewers or wooden skewers that have been soaked in water for 30 minutes.
Grill the kabobs for 8-10 minutes, turning frequently to ensure even cooking.
Serve with your favourite accompaniments and enjoy!