Wiktor Eckhaus (28 June 1930 – 1 October 2000) was a Polish–Dutch mathematician, known for his work on the field of differential equations.

Eckhaus was born into a wealthy family, and raised in Warsaw where his father was managing a fur company.

Wiktor passed the state exam of the Hogere Burgerschool in 1948, and started to study aeronautics at the Delft University of Technology.

In the period 1957–1960 he worked at the Massachusetts Institute of Technology, where Eckhaus earned a PhD in 1959 under Leon Trilling on a dissertation entitled "Some problems of unsteady flow with discontinuities".

Initially he studied the flow around airfoils, leading to his research on the stability of solutions to (weakly) nonlinear differential equations.