A backseat driver (also spelled back-seat driver) is a passenger in a vehicle who is not controlling the vehicle but who excessively comments on the driver's actions and decisions in an attempt to control the vehicle. A backseat driver may be uncomfortable with the skills of the driver, feel out of control since they are not driving the vehicle, or want to tutor the driver while they are at the wheel. Many comment on the speed of the vehicle, or give alternative directions.

Some backseat drivers exhibit this type of behavior simply because they feel the driver is taking risks they would not normally take, while others may have other reasons to be nervous, such as when the driver has a poor driving record. A survey of 2,000 British drivers in early 2018 found that 70% motorists found backseat driving an annoying habit and that life partners were those most likely to interfere. Although only 21% of motorists admitted to backseat driving, half said they have been in arguments due to interfering comments, and five percent admitted to accidentally jumping a red light during an argument with a backseat driver.

Use of the term extends beyond the literal and into the figurative; a "backseat driver" is someone who offers unsolicited advice, directions, or help in a situation where someone else is doing something.