In a large bowl, combine the chicken cubes, olive oil, lemon juice, garlic, oregano, salt and pepper. Mix until all of the ingredients are well combined.
Thread the chicken onto 8 metal skewers or wooden skewers that have been soaked in water for 30 minutes.
Preheat a gas grill to medium heat. Grill the chicken skewers for 10 minutes on each side or until cooked through.