Las Margaritas – Authentic Mexican Restaurant in O’Fallon, MO Since 2015, Las Margaritas has proudly served O’Fallon, MO with authentic Mexican cuisine made from fresh ingredients and bold flavors. As a locally loved Mexican restaurant in O’Fallon, we specialize in generous portions of fan favorites like sizzling fajitas, flavorful burritos, and our signature margaritas. Whether you're joining us for a casual lunch or a festive dinner, our welcoming atmosphere and delicious dishes make every visit memorable. We’re proud to serve guests from Wentzville, Lake St. Louis, St. Peters, Moscow Mills, and surrounding areas. Don’t miss our freshly made guacamole—it’s a must-try! Come experience the best in Mexican food near O’Fallon, MO, and discover why Las Margaritas is a local favorite for flavor, fun, and family.