In a small bowl, whisk together the olive oil, lemon juice, garlic, oregano, thyme, salt, and pepper.
Place the chicken breasts in a resealable plastic bag and pour the marinade over them. Seal the bag and refrigerate for at least 30 minutes.
Preheat the grill to medium-high heat.
Remove the chicken from the marinade and grill for 6-8 minutes on each side, or until fully cooked.
Serve with a side of grilled vegetables or a fresh salad.