In association football, an assistant referee is an official who assists the referee in administering the Laws of the Game during a match. Although assistants are not required under the Laws, at most
Assistant referee signalling that an offside offence has occurred
An assistant referee (front, in black) officiates a match between Partick Thistle and Dundee United
An additional referee for the goal line (in black)
Video assistant referee
Videos
The video assistant referee is a match official in association football who assists the referee by reviewing decisions using video footage and providing advice to the referee based on those reviews.
VAR monitor at the Estadio Monumental David Arellano in Santiago, Chile
A VAR decision during an FA Cup match at the City of Manchester Stadium, Manchester.
A Major League Soccer referee reviewing a play using a sideline monitor
Assistant video assistant referees in action during a Saudi Professional League match