In a bowl, whisk together olive oil, lemon juice, garlic, oregano, salt, and pepper.
Add chicken pieces and toss to coat. Marinate for at least 30 minutes. If you're using wooden skewers, soak them in water for 30 minutes.
Thread chicken onto skewers.
Grill skewers over medium-high heat for 8-10 minutes, turning occasionally, until cooked through.
Squeeze fresh lemon juice over skewers and serve hot.
