The dissociation of ammonia dications induced by 300 eV electron impact has been studied using a cold target recoil-ion momentum spectroscopy. Three regimes were found in the evolution of the produced NH32+ ions, i.e. stable (long-lived), slowly dissociating (metastable), and promptly dissociating. Multiple dissociation channels of NH32+ have been distinguished and identified by ion–ion coincidence technique. The kinetic energy release of the deprotonation dissociation channel NH32+ → H+ + NH2+ and the bond-rearrangement channel NH32+ → H2+ + NH+ have been obtained. The dynamic information and complex fragmentation pathways were analyzed by combining Dalitz plot and Newton diagram for the three-body dissociation channel NH32+ → H+ + NH+ + H. Strong correlation between the dynamic processes of H+, H loss, and the kinetic energy release was found.