Massen-Niederlausitz (Lower Sorbian: Mašow, pronounced [ˈmaʃɔw]) is a municipality in the Elbe-Elster district, in Lower Lusatia, Brandenburg, Germany.

From 1815 to 1947, the constituent localities of Massen-Niederlausitz (Babben, Betten, Lindthal, Massen, Gröbitz and Ponnsdorf) were part of the Prussian Province of Brandenburg. From 1952 to 1990, they were part of the Bezirk Cottbus of East Germany. On 31 December 1997, the municipality of Massen-Niederlausitz was formed by merging the municipalities of Babben, Betten, Lindthal and Massen. On 31 December 2001, the municipalities of Gröbitz and Ponnsdorf were merged into it.

Massen-Niederlausitz:
Population development within the current boundaries (2013)

Year Population 1875 1 795 1890 1 715 1910 1 979 1925 2 062 1933 2 202 1939 2 426 1946 3 295 1950 3 230 1964 2 639 1971 2 576

Year Population 1981 2 360 1985 2 343 1989 2 305 1990 2 263 1991 2 198 1992 2 201 1993 2 261 1994 2 263 1995 2 253 1996 2 258

Year Population 1997 2 272 1998 2 328 1999 2 411 2000 2 412 2001 2 429 2002 2 382 2003 2 362 2004 2 350 2005 2 309 2006 2 236

Year Population 2007 2 214 2008 2 190 2009 2 129 2010 2 093 2011 2 066 2012 2 044 2013 2 017 2014 1 981 2015 1 962 2016 1 919