Ivan Vidav (born January 17, 1918) is a Slovenian mathematician.
Ivan Vidav was born in Opčine near Trieste (Slovenian Trst), Italy. He is Josip Plemelj's student. Vidav got his Ph.D. under Plemelj's advisory in 1941 at the University of Ljubljana with a dissertation Kleinovi teoremi v teoriji linearnih diferencialnih enačb (Klein's theorems in the theory of linear differential equations).
Vidav's main research interest are differential equations, functional analysis and algebra. He is a regular member of Slovenian Academy of Sciences and Arts. He was awarded the Prešeren Award.
From 1988 he is an honourable member of the Society of Mathematicians, Physicists and Astronomers of Slovenia (DMFA).