Marc Edward Culler (born November 22, 1953) is an American mathematician who works in geometric group theory and low-dimensional topology.

In particular, Culler and Shalen used the Bass–Serre theory, applied to the function field of the SL(2,C)-Character variety of a 3-manifold, to obtain information about incompressible surfaces in the manifold.

Based on this work, Shalen, Cameron Gordon, John Luecke, and Culler proved the cyclic surgery theorem.

Another important contribution by Culler came in a 1986 paper with Karen Vogtmann called "Moduli of graphs and automorphisms of free groups".

Culler is one of the authors of a 1994 paper called "Plane curves associated to character varieties of 3-manifolds"[5] which introduced the A-polynomial of a knot[6] or, more generally, of a 3-manifold with one torus boundary component.