A turnkey or a turnkey project is a project in which separate entities are responsible for setting up a plant or equipment (e.g. trains/infrastructure) and for putting it into operation. It can include contractual actions at least through the system, subsystem, or equipment installation phase and may include follow-on contractual actions, such as testing, training, logistical, and operational support. It is often given to the best bidder in a procurement process.
Turnkey projects can also be extended, known as turnkey plus, where there is perhaps a small equity interest by the supplier and it will later on continue its operation through a management contract or licensing.
This is commonly used in motorsports to describe a car being sold with drivetrain (engine, transmission, etc.) as a racer may prefer to keep the pieces to use in another vehicle to preserve a combination. Similarly, this term may be used to advertise the sale of an established business, including all the equipment necessary to run it, or by a business-to-business supplier providing complete packages for business start-up.
The term turnkey is also often used in the technology industry, most commonly to describe pre-built computer "packages" in which everything needed to perform a certain type of task (e.g. audio editing) is put together by the supplier and sold as a bundle. This often includes a computer with pre-installed software, various types of hardware, and accessories. Such packages are commonly called appliances.
In real estate, Turn-Key is defined as delivering a location that is ready for occupation. The Turn-Key process includes all of the steps involved to open a location including the site selection, negotiations, space planning, construction coordination and complete installation.