The Kelly bag (formerly known as the Sac à dépêches) is a leather handbag designed by the Paris-based, high-fashion luxury-goods manufacturer Hermès. The bag was redesigned several times before it was popularized by and then named after the American actress and Monégasque princess Grace Kelly. The bag is now an expensive status symbol.

The Kelly bag is a trapezium closed with two straps. Four studs on the bottom, itself made of three layers of leather, enable it to stand on the ground. It is sold in eight sizes, ranging from 15 centimetres (5.9 inches) to 50 centimetres (20 inches). The padlock, keys and hardware are made of white or yellow gold. The current model Kelly bag, the Kelly II, comes in two distinct styles, as did its predecessor, the Kelly I. The sellier style is a rigid construction including a stiffening layer between the outer leather and inner lining, with the side and bottom stitching clearly visible; the retourné style is a softer construction, wherein the bag is sewn and then turned inside-out, hiding the exterior side stitching.

The Kelly II, released in 2000 as an update to the original Kelly, has a double ring at the top handle, designed to attach to a shoulder strap; the original Kelly, while often sold with a shoulder strap, features a single-ring design. The construction of each Kelly bag requires 18 to 25 hours of handicraft, with each item being created by a single artisan, resulting in high retail prices. By the mid-1990s, a Kelly bag was priced at US$3,500, and as of 2019, prices range from US$8,500 to US$13,000, with exotic leathers priced higher.

Alfred Hitchcock has been credited with bringing the handbag into the limelight. In 1954, Hitchcock allowed the costume designer Edith Head to purchase Hermès accessories for the film To Catch a Thief, starring Grace Kelly. According to Head, Kelly “fell in love” with the bag. In 1956 she became princess of Monaco and was photographed using the handbag to shield her growing belly from the paparazzi during her first pregnancy. That photograph was featured in Life magazine.Princess Grace was a fashion icon, and the handbag immediately achieved great popularity.Although the handbag instantly became known as the Kelly bag, it was not officially renamed until 1977.

The handbag with which Princess Grace was photographed was loaned from the palace archives of Monacoand displayed in the Victoria and Albert Museum in April 2010, along with other notable wardrobe items owned by the princess.The “star exhibit” of the show contains scuffs and marks, as the wardrobe thrifty princess carried it for many years.Hermès now creates 32 styles of handbags, but the Kelly persists as the manufacturer’s best-seller.