A sport utility vehicle, or SUV, is a passenger vehicle which combines the towing capacity of a pickup truck with the passenger-carrying space of a minivan or station wagon together with on or off road ability. Most SUVs are designed with a roughly square cross-section, an engine compartment, a combined passenger and cargo compartment, and no dedicated trunk. Most mid-size and full-size SUVs have three rows of seats with a cargo area directly behind the last row of seats. Compact SUVs and mini SUVs may have five or fewer seats.

It is known in some countries as an "off-road vehicle" or "four-wheel drive", often abbreviated to "4WD" or "4x4", pronounced "four-by-four". However, not all SUVs have four-wheel drive capabilities. Conversely, not all 4WD passenger vehicles are SUVs. Off-road vehicles are a very different class of vehicles, being vehicles primary built for off-road use. Although some SUVs have off-road capabilities, this is often a secondary role and they often do not have the ability to switch between 2WD, 4WD high gearing and 4WD low gearing.

More recently, manufacturers have responded to buyers' complaints that SUVs "drive like trucks" and demands for "carlike ride" with a new type of SUV. A new category, the crossover SUV uses car design and components for lighter weight and better fuel efficiency, but is no longer designed or recommended by the manufacturer for off-road usage or towing.