A station wagon (US, also wagon) or estate car (UK, also estate) is an automotive body-style variant of a sedan with its roof extended rearward over a shared passenger/cargo volume with access at the back via a third or fifth door (the liftgate, or tailgate), instead of a trunk/boot lid. The body style transforms a standard three-box design into a two-box design—to include an A, B, and C-pillar, as well as a D-pillar. Station wagons can flexibly reconfigure their interior volume via fold-down rear seats to prioritize either passenger or cargo volume.

The American Heritage Dictionary defines a station wagon as "an automobile with one or more rows of folding or removable seats behind the driver and no luggage compartment but an area behind the seats into which suitcases, parcels, etc., can be loaded through a tailgate."

When a model range includes multiple body styles, such as sedan, hatchback, and station wagon, the models typically share their platform, drivetrain, and bodywork forward of the A-pillar, and usually the B-pillar. In 1969, Popular Mechanics said, "Station wagon-style ... follows that of the production sedan of which it is the counterpart. Most are on the same wheelbase, offer the same transmission and engine options, and the same comfort and convenience options."

Station wagons have evolved from their early use as specialized vehicles to carry people and luggage to and from a train station. The demand for station wagon body style has faded since the 2010s in favor of the crossover or SUV designs.

Reflecting the original purpose of transporting people and luggage between country estates and railway stations, the station wagon body style is called an "estate car" or "estate" in the United Kingdom or a "wagon" in Australia and New Zealand.

Either horse-drawn or automotive, the earliest use of the station wagon description would be considered to describe utility vehicles or light trucks. The depot hackney or taxi, often on a Model T chassis with an exposed wood body, most often found around railroad stations, was the predecessor of the station wagon body style in the United States. These early models with exposed wooden bodies became known as woodies. By the 1920s the status of the station wagon description changed to consider them as vehicles for passengers.

In Germany, the term "kombi" is used. This is short for Kombinationskraftwagen ("combination motor vehicle"). "Kombi" is also the term used in Poland.

In Russia and some post-Soviet countries, this type of car is called "universal".