The Hermes Kelly bag is a coveted bag. Like its muse, Grace Kelly, this bag is the definition of timeless elegance. The original prototype of this bag dates back to 1892 when Hermes developed a large bag to hold a saddle; the prototype was modified over the decades but the Kelly produced by Hermes today is similar to the Sac a Depeches introduced in the 1930s. In 1954, Grace Kelly was given the bag to use in the Hitchcock movie To Catch A Thief and she became an immediate fan. She wore it regularly after her marriage to Price Rainier of Monaco in 1956. The pregnant Princess Grace was photographed by Life Magazine wearing the bag to hide her growing belly and the media and public immediately dubbed the bag the Kelly bag. Hermes officially named it the Kelly in 1977.

The Kelly is immediately recognizable by its trapezium shape, its thin straps with metal plates on end of each strap (one engraved) that meet on a center toggle, its single rolled handles and its bell shaped key fob (clochette) and matching lock, it is an outstanding piece of workmanship. Each bag takes up to 25 hours to produce and each is hand sewn, buffed, painted and polished by Hermes skilled craftsman in Hermes' factories. In as much as leathers come from a variety of tanners and bags are produced by individual artisans, each bag is likely to have its own unique details.

Kelly handbags come in two styles – Retourne and Sellier. The Retourne, also called relaxed or souple, has the side seams stitched on the inside of the bag, creating a more relaxed handbag. The Sellier, also called rigide, has the side seams stitched on the exterior giving the bag a stiffer and more triangular form. Kelly bags come in 20cm, 25cm, 28cm, 35cm and 40cm sizes.

Kelly bags are stamped with a letter signifying the year of production and with a craftsman's code designating the specific person(s) who hand produced the bag. In addition to wide range of leathers, Kellys are produced in exotic skins such as ostrich, lizard and crocodile. The bag is typically accented by palladium or gold hardware.

The Kelly has the advantage of having a shoulder strap enabling it to be worn on the shoulder, in addition to hand or forearm. This option makes it popular with younger Hermes devotees.