Louise Mai Jansen (born April 14, 1984) is a Danish former swimmer, who specialized in freestyle and individual medley events. She is an eighteen-time national champion and a Nordic record holder in the freestyle and medley (both 200 m). She is also an eighth-place finalist in the 200 m individual medley at the 2010 European Aquatics Championships in Budapest, Hungary with a time of 2:17.37, just eight seconds off the record set by Julie Hjorth-Hansen in 2009. Jansen is an economics graduate, majoring in mathematics at Copenhagen Business School in Copenhagen.