Kai Behrend is a German mathematician.

He is a professor at the University of British Columbia in Vancouver, British Columbia, Canada.

His work is in algebraic geometry and he has made important contributions in the theory of algebraic stacks, Gromov–Witten invariants and Donaldson–Thomas theory (cf.

He is also known for Behrend's formula, the generalization of the Grothendieck–Lefschetz trace formula to algebraic stacks.

[3] He was elected to the 2018 class of fellows of the American Mathematical Society.