Josef Stoer (born 21 June 1934) is a German mathematician specializing in numerical analysis and professor emeritus of the Institut für Mathematik of Universität Würzburg.

[1] Stoer was born in Meschede, and earned his Ph.D. in 1961 at Johannes Gutenberg-Universität Mainz under Friedrich Ludwig Bauer and Klaus Samelson.

[2] He is the author (with Roland Bulirsch) of Introduction to Numerical Analysis, a standard reference for the theory of numerical methods.

[3] He has an honorary doctorate from the University of Augsburg (2007) and the Technical University of Munich (1997)[4] and is a member of the Bavarian Academy of Sciences (1981).

[5] The Bulirsch–Stoer algorithm is named after him and Roland Bulirsch.