Pat chicken dry and pound chicken if some parts are too thick. Combine the olive oil, lemon juice, lemon zest, oregano, garlic, salt and pepper in a bowl or resealable freezer bag. Add chicken and toss well to combine. Marinate chicken for at least 30 minutes.

Preheat grill or grill pan to medium high heat. Place chicken on the grill for 5 to 7 minutes. Use tongs to flip chicken and cook until juices run dry, approximately 5 to 7 more minutes. Discard extra marinade.