Jacket lapels are the folded flaps of cloth on the front of a jacket or coat, and are most commonly found on formal clothing and suit jackets. Usually they are formed by folding over the front edges of the jacket or coat and sewing them to the collar, an extra piece of fabric around the back of the neck, as shown in the image.

There are three basic forms of lapels: notched, peaked and shawl. Notched lapels, the most common, are usually seen on business suits. Peaked lapels are more formal, and nearly always used on double breasted jackets or coats. Shawl lapels are usually carried by dinner jackets.

The notched lapel (American English), step lapel or step collar (British English) is sewn to the collar at an angle, creating a step effect. This is the standard on single breasted suits, and is used on nearly all suit jackets, blazers, and sports jackets. The size of the notch can vary, and a small notch is called fishmouth.

The peaked lapel (American English), double breasted style lapel or pointed lapel (British English), is the most formal, featuring on double-breasted jackets, and is now always worn with all formal coats such as a tailcoat or morning coat, and also commonly with a dinner jacket (both single and double breasted). In the late 1920s and 1930s, the single breasted peaked lapel jacket was considered a very stylish design. The feature was carried into day clothing by the increasing popularity of the peaked dinner jacket. This has gone in and out of vogue periodically, made popular once again during the 1970s by designers such as Armani, and is currently a trending style in the 2010s. The ability to properly cut peak lapels on a single-breasted suit is one of the most challenging tailoring tasks, even for very experienced tailors.