Losna is a lake which lies in the municipalities of Ringebu and Øyer in Innlandet county, Norway. Losna is a part of the Gudbrandsdalslågen river, which is in this region so broad and runs so slowly that this stretch is recognized as a lake. The 9.84-square-kilometre (3.80 sq mi) lake has a length of 11 kilometres (6.8 mi) and it lies at an elevation of 181 metres (594 ft) above sea level and the maximum depth of the lake is 55 metres (180 ft) below the surface. The European route E6 highway and the Dovrebanen railway line both run along the shores of the lake.

• List of lakes in Norway