Dag Alexander Olsen (born 9 September 1989) is a Norwegian professional footballer who plays as a forward or winger for Gjøvik-Lyn.
After finishing his graduation in Tottenham Hotspur's youth setup, Olsen signed with Valencia CF. He made his senior debuts with the reserves in the 2008âÂÂ09 season, in Segunda División B. Olsen also appeared three times with the main team, starting in a 1âÂÂ1 away draw against Al Ain FC and scoring twice vs Standard Liege.
After being sparingly used in his third season, Olsen left the Valencians and signed with Odd Grenland BK. On 2 September he made his debut, coming on as a late substitute in a 1âÂÂ0 away win over FK Haugesund.
On 29 October 2013, Olsen returned to Spain, signing with CD Castellón until 23 December, to get back to fitness after a crucial ligament rupture in Norway. In March the following year he moved teams and countries again, signing a one-year deal with Fredrikstad FK. Ahead of the 2016 season he returned home to Gjøvik and FK Gjøvik-Lyn.