A level crossing, also known as a grade crossing, railway crossing, or railroad crossing, is an intersection where a railway line and a road meet each other on the same level. This means that the grades (the road and the track) are not separated by using a bridge or a tunnel. Level crossings can also occur when a light rail line with separate right-of-way or reserved track crosses a road in the same fashion.

To avoid collisions, warning/control devices are required at grade crossings just like intersecting roads need stop signs or traffic signals. Active grade crossings have active warning and control devices such as bells, flashing lights, and gates, in addition to passive warning devices such as crossbucks (the familiar x-shaped signs that mean yield to the train), yield or stop signs, and pavement markings. Passive grade crossings have only passive warning devices.

There are more than 100,000 level crossings in Europe and more than 200,000 in North America. In rural regions with sparse traffic, the least expensive type of level crossing to operate is one without flagmen or gates, with only a warning sign posted. This type has been common across North America and in many developing countries.

Collisions between highway vehicles and trains have been, until recently (1996), the greatest source of injuries and fatalities in the railroad industry. As a result of the Grade Crossing Action Plan, and the continuous research effort funded by the Federal Railroad Administration (FRA), the number of fatalities and injuries at grade crossings has decreased.