Guðjón Árni Antoníusson (born 3 September 1983) is an Icelandic former footballer who is currently manager of Víðir.
After spending a year in the club's reserve team, Guðjón made his league debut for Keflavík in the 2–2 draw with Grindavík on 8 July 2002.
Over the following ten seasons, he went on to make more than 200 appearances for the side in all competitions and was involved in both the 2004 and 2006 Icelandic Cup finals, both of which ended in wins for Keflavík.
[1] After retiring from football, Antoníusson took charge of 2. deild karla side Víðir in June 2017.
[2] After a successful first season, in which the club finished third in the league, he signed a new one-year contract extension in September 2017.