Dennis Otzen Jensen (born December 2, 1974) is a Danish former swimmer, who specialized in sprint freestyle and butterfly events.
He is a 2000 Olympian, and a member of Triton Swimming Club in Skovlunde (Danish: Svømmeklubben Triton) under his personal coach John Ludvigsen.Jensen competed in three swimming events, including all freestyle relays, for Denmark at the 2000 Summer Olympics in Sydney.
He achieved a FINA B-cut of 55.31 (100 m butterfly) from the European Championships in Helsinki.
In the 100 m butterfly, Jensen challenged seven other swimmers in heat four, including Yugoslav teenager Milorad Cavic (aged 16), who later disqualified for a false start.
He raced to a fifth seed and forty-second overall by almost a full body length behind winner Simão Morgado of Portugal in 55.70.
A member of the Danes, he also placed eighteenth in the 4×100 m freestyle relay (3:24.78), and eleventh in the 4×200 m freestyle relay (7:24.63).