Camillo De Lellis (born 11 June 1976) is an Italian mathematician who is active in the fields of calculus of variations, hyperbolic systems of conservation laws, geometric measure theory and fluid dynamics.

Prior joining the faculty of the Institute for Advanced Study, De Lellis was a professor of mathematics at the University of Zurich from 2004 to 2018.

[5][6] There Almgren proved his famous regularity theorem asserting that the singular set of an m-dimensional mass-minimizing surface has dimension at most m − 2.

De Lellis has also worked on various aspects of the theory of hyperbolic systems of conservation laws and of incompressible fluid dynamics.

In particular, together with László Székelyhidi Jr., he has introduced the use of convex integration[7] methods and differential inclusions to analyse non-uniqueness issues for weak solutions to the Euler equation.