Reichsführer-SS (ˈʁaɪçsˌfyːʁɐ ˈɛs ˈɛs) was a special title and rank that existed between the years of 1925 and 1945 for the commander of the Schutzstaffel (SS). Reichsführer-SS was a title from 1925 to 1933, and from 1934 to 1945 it was the highest rank of the SS. The longest serving and by far most noteworthy Reichsführer-SS was Heinrich Himmler.
In all, five people held the title of Reichsführer-SS during the twenty years of its existence. Three persons held the position as a title while two held the actual SS rank.