BMC ADO17 is the model code used by the British Motor Corporation (BMC) for a range of large family cars manufactured from September 1964 to 1975. The car was initially sold under the Austin marque as the Austin 1800, then by Morris as the Morris 1800, by Wolseley as the Wolseley 18/85, and later the Austin 2200, Morris 2200 and Wolseley Six. The 1800 was voted European Car of the Year for 1965.

The car was unconventional in its appearance in 1964, with its large glasshouse and spacious, minimalist interior including leather, wood, and chrome features plus an unusual instrument display with ribbon speedometer and green indicator light on the end of the indicator stalk. There was a chrome "umbrella handle" handbrake under the dashboard parcel shelf, and the two front seats met in the middle and could be used, on occasion, as a bench seat. Both Alec Issigonis and Pininfarina worked on its exterior. The technology "under the skin" was also unconventional and ahead of its time, including Hydrolastic suspension and an example of inertia-controlled brake proportioning, in the form of a valve which transferred braking force between front and rear axles as a function of sensed deceleration rather than as a function of fluid pressure.

Progressive improvement was a feature of most cars in this period, but the number and nature of the changes affecting the early years of the Austin 1800 looked to some as though the car had been introduced with insufficient development. In December 1964, a month after its launch, reclining front seats and the option of an arm rest in the middle of the back seat were added to the specification schedule.

A nickname of 'Landcrab' was given to the car by some, derived from the car's unusual proportions, being much wider and lower than most other cars in its class. The car's successful use in endurance rallies came about because, while the car was never particularly fast, its strong bodyshell and sophisticated suspension allowed it to reliably maintain competitive average speeds over long distances on poor roads. The car's stance, strength and slow-but-sure nature over rough ground put the BMC rally crews in mind of a terrestrial crab. The nickname stuck and became widespread in the press and public. The Mark I's doors were later used on the Austin Maxi and larger Austin 3-Litre model.