The traditional and most commonly used meat for tacos al pastor is pork. Specifically, pork shoulder or pork butt (also known as pork shoulder butt or Boston butt) is often preferred due to its marbling and tenderness. The pork shoulder has enough fat to keep the meat moist and flavorful during cooking. Thinly sliced pork shoulder works exceptionally well for tacos al pastor as it absorbs the marinade flavors and cooks quickly on the grill or stovetop, resulting in juicy and delicious meat.