The penalty area or 18-yard box (also known less formally as the penalty box or simply box) is an area of an association football pitch. It is rectangular and extends 16.5m (18 yd) to each side of the goal and 16.5m (18 yd) in front of it.

Within the penalty area is the penalty spot, which is 11m (12 yd) from the goal line, directly in-line with the centre of the goal.

A penalty arc (often informally called "the D") adjoins the penalty area, and encloses the area within 9.15m (10 yd) of the penalty spot. It does not form part of the penalty area and is only of relevance during the taking of a penalty kick, when any players inside the arc are adjudged to be encroaching.

Within the penalty area is another smaller rectangular area called the goal area (colloquially the "six-yard box"), which is delimited by two lines starting on the goal-line 5.5 metres (6 yd) from the goalposts and extending 5.5 metres (6 yd) into the pitch from the goal-line, and the line joining these. Goal kicks and any free kick by the defending team may be taken from anywhere in this area. Indirect free kicks awarded to the attacking team within the goal area are taken from the point on the line parallel to the goal line (the "six-yard line") nearest where the infringement occurred; they cannot be taken any closer to the goal line. Similarly drop-balls that would otherwise occur closer to the goal line are taken on this line.

Previously, penalty areas extended the width of the field, but were reduced to their current dimensions in 1901.