Dennis Geiger (born 10 June 1998) is a German professional footballer who plays as a midfielder for club Aberdeen on loan from TSG Hoffenheim.
Geiger was born in Mosbach, Baden-Württemberg and plays for Hoffenheim. He played for Alemannia Sattelbach from 2008-2009 and has played for 1899 Hoffenheim since 2009.
Geiger signed his professional contract with Hoffenheim in January 2017, he represented them from U12s and has represented Germany at all levels from the U15. In May of 2015, he finished second with the Germany U17 at the European Championships in Bulgaria. In spring of 2016, he played a big role in TSG U19s' run to the final of the German Championship. In the final itself, he scored the 1-1 equaliser in the 5-3 loss to Borussia Dortmund.
On 19 August 2017, he made his professional debut in a win over Werder Bremen. He also made his UEFA Europa League debut on the same month.
On 2 February 2026, Geiger joined Aberdeen in Scotland on loan with an option to buy. On 21 February 2026, on his debut against Motherwell, he was sent off for a dangerous tackle.
Described as a holding midfielder, Geiger - in the reserves at the time was a surprising choice to Hoffenheim fans.