Sydower Fließ (German pronunciation: [ˈzyːdoːɐ̯ ˈfliːs]) is a municipality in the district of Barnim in Brandenburg in Germany.

The municipality of Sydower Fließ was formed on 27 September 1998 by merging the municipalities of Grüntal and Tempelfelde.

From 1815 to 1947, the constituent localities of Sydower Fließ were part of the Prussian Province of Brandenburg, from 1947 to 1952 of the State of Brandenburg, from 1952 to 1990 of the East German Bezirk Frankfurt and since 1990 again of Brandenburg, since 1998 united as Sydower Fließ.

Sydower Fließ: Population development
within the current boundaries (2020)

Year Pop. ±% p.a. 1875 1,014 —     1890 1,068 +0.35% 1910 1,013 −0.26% 1925 1,062 +0.32% 1933 1,034 −0.33% 1939 1,040 +0.10% 1946 1,189 +1.93% 1950 1,279 +1.84% 1964 1,109 −1.01% 1971 1,172 +0.79% 1981 984 −1.73% 1985 954 −0.77% 1989 958 +0.10% 1990 961 +0.31% 1991 923 −3.95%

Year Pop. ±% p.a. 1992 898 −2.71% 1993 888 −1.11% 1994 884 −0.45% 1995 872 −1.36% 1996 873 +0.11% 1997 881 +0.92% 1998 931 +5.68% 1999 921 −1.07% 2000 924 +0.33% 2001 921 −0.32% 2002 931 +1.09% 2003 933 +0.21% 2004 907 −2.79% 2005 905 −0.22% 2006 889 −1.77%

Year Pop. ±% p.a. 2007 889 +0.00% 2008 901 +1.35% 2009 884 −1.89% 2010 866 −2.04% 2011 846 −2.31% 2012 831 −1.77% 2013 863 +3.85% 2014 886 +2.67% 2015 921 +3.95% 2016 933 +1.30% 2017 967 +3.64% 2018 982 +1.55% 2019 973 −0.92% 2020 977 +0.41%