| Office: | Member of the Folketing |
| Termstart: | 13 November 2007 |
| Constituency: | East Jutland |
| Birth Date: | 29 June 1967 |
| Birth Place: | Grenaa, Denmark |
| Party: | Social Democrats |
Leif Lahn Jensen (born 29 June 1967) is a Danish politician who is a member of the Folketing for the Social Democrats. He was elected into parliament at the 2007 Danish general election.
Jensen was a member of the municipal council in Grenaa Municipality from 2002 to 2006. In 2007 the municipality was merged with the municipalities of Nørre Djurs, Rougsø and part of Sønderhald to form Norddjurs Municipality. Jensen sat in this municipal council from 2006 to 2007.[1]
Jensen was elected to parliament in the 2007 election, and reelected in the 2011, 2015 and 2019 elections.[2]