Elfriede Lohse-Wächtler (born Anna Frieda Wächtler; 4 December 1899 – 31 July 1940) was a German painter of the avant-garde whose works were banned as "degenerate art", and in some cases destroyed, by the Third Reich.
She was murdered in a former psychiatric institution at Sonnenstein castle in Pirna under Action T4, a forced euthanasia program of Nazi Germany.
Since 2000, a memorial center for the T4 program in the house commemorates her life and work in a permanent exhibition.