A repair kit or service kit is a set of items used to repair a device, commonly comprising both tools and spare parts. Many kits are designed for vehicles, such as cars, boats, airplanes, motorbikes, and bicycles, and may be kept with the vehicle in order to make on-the-spot repairs. Some are considered essential safety equipment, and may be included survival kits. In the military, personnel crossing large water bodies in aircraft may be equipped with a raft and raft repair kit. Other kits, such as those for watch repair or specific engine components, are used by professionals. Depending on the type, a repair kits may be included when buying a product, or may be purchased separately.Road vehicles often include basic tools and spare parts which commonly fail. A bicycle repair kit, for example, normally contains tools as well as patches and glue to repair a punctured tire. Other kits that include patches and glue are used to fix holes in fabric items such as inflatable boats and tents.

Watercraft normally contain both safety equipment and repair kits as part of their emergency equipment.

Some automobiles, such as the kit valve cores tools, have an optional repair kit available. The Mercedes-Benz  engine has an optional repair kit to help replace seals. The 1905 Gale Model A came with a repair kit.

In aerospace, kits have been developed for repairing the thermal protection tiles on the Space Shuttle and to fix space suits.

Professionals who repair and maintain electronic equipment may have a kit containing a soldering iron, wire, and components such as transistors and resistors.

In medicine, a repair kit consisting of a plug and plastic mesh may be used during inguinal hernia surgery.

A particular trade may use a repair kit as part of normal work, such as in watch repair and at automobile repair shops.