This book contains the refereed proceedings of the 11th International Symposium on Mathematical Morphology, ISMM 2013 held in Uppsala, Sweden, in May 2013. The 41 revised full papers presented together with 3 invited papers were carefully reviewed and selected from 52 submissions. The papers are organized in topical sections on theory; trees and hierarchies; adaptive morphology; colour; manifolds and metrics; filtering; detectors and descriptors; and applications.