Ford Prefect is a fictional character in the radio series (and subsequent books, television series, and so on) The Hitchhiker's Guide to the Galaxy by the British author Douglas Adams.

Ford is a good friend of the main character, an ordinary Earthman named Arthur Dent, who has known him for several years and believes him to be from the town of Guildford in Surrey. However, he is actually an alien from a small planet in the vicinity of Betelgeuse, and had originally only come to Earth to do some research for an article he was writing on it for the Guide.

Although Ford had taken great care to blend into Earth society, he had "skimped a bit on his preparatory research", and thought that the name "Ford Prefect" would be "nicely inconspicuous". Adams later clarified in an interview that Ford "had simply mistaken the dominant life form". The Ford Prefect is, in fact, a line of inexpensive automobiles manufactured in the United Kingdom. Adams later observed that this joke was lost on U.S. audiences who assumed it was a typing error for "perfect". It is also of note that in the French version of the novel, Ford's name was changed to "Ford Escort".

Ford came to Earth for a week, and got stuck there for fifteen years, departing only when a fleet of Vogon construction ships appear in the first episode, taking Arthur Dent with him. For the listener/reader/viewer, Ford is the source of much explanation of the weird universe that Arthur finds himself in, for example the importance of knowing where your towel is, sticking fish in your ear, and why the greatest cooks in the universe cook such bad food on Vogon spaceships.

In the novel, we are told that Ford's original name is "only pronouncible in an obscure Betelgeusian dialect" which was almost wiped out by the "Great Collapsing Hrung Disaster of Gal./Sid./Year 03758", a mysterious catastrophe which took place on the planet of Betelgeuse Seven and which Ford's father was the only man to survive. Ford never learned to pronounce his original name. At school, he was nicknamed "Ix", which translates as "boy who is not able satisfactorily to explain what a Hrung is, nor why it should choose to collapse on Betelgeuse Seven".

Despite all this, his semi-cousin Zaphod Beeblebrox calls him "Ford" the first time they are reunited. Douglas Adams has explained this by indicating that, prior to visiting Earth, Ford went back in time and changed his name at birth to Ford Prefect; hence he has now always been called Ford.

In the original radio series and subsequent LP adaptation Ford was played by Geoffrey McGivern. On television he was played by David Dixon, and in the upcoming theatrical movie he is going to be played by Mos Def.