Yes, sirloin steak is a great choice for fajitas. It is lean yet flavorful, making it ideal for achieving the perfect texture when cooked with bell peppers and onions. Plus, sirloin steak has enough fat marbling to give your fajitas a beefy flavor without being overly greasy or oily. If you’re looking for a lean option, then sirloin is definitely one to consider when making your next batch of fajitas.