Slice meat thinly
Marinate with olive oil, lemon juice, garlic, oregano, salt, and pepper
Refrigerate for at least 1 hour
Heat a skillet, grill, or oven
Cook the meat until browned and fully cooked
Warm pita bread
Slice tomatoes, onions, and lettuce
Mix yogurt, garlic, cucumber, lemon juice, and dill for tzatziki
Fill pita with meat and vegetables
Add tzatziki sauce
Serve immediately