Guðjón Þórðarson (Icelandic pronunciation: ?['kv?ðjoun '?ourðar?s?n]; born 14 September 1955) is an Icelandic former footballer and manager.
He has previously been manager of ÍA, KA, KR, Keflavík, Notts County, Iceland, Stoke City, Barnsley, Start in Norway, Crewe Alexandra and provincial Icelandic club BÍ/Bolungarvík, from which he was sacked in October 2011 after having guided the team to a 6th-place finish in the B division and a semi-finals spot in the league cup, during his year in charge.
On 7 November 2011 he was appointed new manager of Grindavík, succeeding Ólafur Örn Bjarnason, that had been manager and player of the club for one year, but resigned as manager so he could fully focus on his performance on the pitch.
Guðjón has three sons who have also played professional football, namely: Bjarni, Joey and Þórður Guðjónsson.