Flap Steak vs Sirloin Flap — What's the Difference?
Quick Answer
Flap Steak (flap steak (sirloin flap)) and Sirloin Flap (sirloin flap) are not the same cut: Flap Steak is sirloin primal (Bottom sirloin, obliquus internus abdominis muscle); Sirloin Flap is sirloin primal (sirloin flap / bottom sirloin flap).
Canonical entities: Flap Steak · Sirloin Flap
Side-by-side
| flap steak | sirloin flap | |
|---|---|---|
| Primal | sirloin | sirloin |
| Muscle / location | Bottom sirloin, obliquus internus abdominis muscle | sirloin flap / bottom sirloin flap |
| Character | A thin, coarse-grained steak from the bottom sirloin. The American name for what the French call bavette d'aloyau. Open grain absorbs marinades extremely well. Popular for fajitas, stir-fry, and carne asada. Often confused with skirt steak but from a different location entirely. | Thin, loose-grained flap from the bottom sirloin; overlaps skirt/flank in some regional breakdowns. |
Key differences
- Texture and slicing: compare fibrous, grain-heavy cuts vs more tender steak-style muscles based on each cut’s description.
- Retail naming diverges by country—always map through a canonical cut when translating menus or labels.
When to use each
Flap Steak
Pick Flap Steak when you want its specific marbling/texture profile: A thin, coarse-grained steak from the bottom sirloin. The American name for what the French call bavette d'aloyau. Open grain absorbs marinades extremely well. Popular for fajitas, stir-fry, and carne asada. Often confused with skirt steak but from a different location entirely.
Sirloin Flap
Pick Sirloin Flap when its primal/muscle traits fit the dish: Thin, loose-grained flap from the bottom sirloin; overlaps skirt/flank in some regional breakdowns.
Flap Steak and Sirloin Flap are different canonical muscles/primals: Flap Steak is sirloin (Bottom sirloin, obliquus internus abdominis muscle); Sirloin Flap is sirloin (sirloin flap / bottom sirloin flap).
Choose based on tenderness, marbling, grain direction, and how you plan to cook (sear vs braise vs slice thin).
Read the full guides: flap steak (what-is) · sirloin flap (what-is) · flap steak hub · sirloin flap hub