Wilhelm Müller-Wismar (20 May 1881 – 13 October 1916) was a German ethnographer.
A native of Wismar, he graduated in 1905 from the University of Berlin, where he studied ethnography and anthropology under Felix von Luschan (1854-1924).
From 1908 to 1910 he was a member of a scientific mission to the South Pacific that was coordinated by Georg Thilenius (1868-1937) of the Hamburg Museum of Ethnography.
On the expedition he spent nine months on the island of Yap, about which an important scientific treatise was later published.
Müller-Wismar died from typhoid on 10 October 1916, at the age of 35 in Malang, Java.