Greek chicken gyros are a fresh, flavorful meal made with yogurt-marinated chicken, warm pita, and classic toppings like tzatziki, cucumber, red onion, and feta.
In a large bowl, whisk together the Greek yogurt, lemon juice, minced garlic, oregano, salt, and pepper until smooth. Add the chicken breasts and turn to coat evenly. Cover and refrigerate for at least 30 minutes, or up to a few hours for deeper flavor.
Preheat a grill or large skillet over medium-high heat. Lightly oil the grates or pan to prevent sticking. Remove the chicken from the marinade, letting any excess drip off.
Cook the chicken for 5–7 minutes per side, depending on thickness, until cooked through and lightly browned. The chicken should reach an internal temperature of 165°F. Transfer to a plate and let rest for a few minutes before slicing.
While the chicken rests, warm the pita or flatbreads until soft and pliable. Spread tzatziki sauce over each pita, then layer with romaine, cucumber, red onion, olives, and sliced chicken. Finish with feta cheese, fold, and serve immediately.