The objective of this paper is to document patterns of complexity in the aggressive and reproductive behavior of mantis shrimps, and to test the hypothesis that lineages with more complex behavior evolve more rapidly than those with relatively simple behavior. Stomatopod taxa that occupy preformed holes in coral or rock habitats show more specialized social behavior, more elaborate morphological adaptations for aggression (color patterns, ornamentation, and armor), complex courtship and copulation, and more extensive parental care than taxa that excavate their own burrows in mud or sand substrates. Similarly, taxa of large body size in both coarse and level bottom habitats show more complex agonistic interactions and associated morphological adaptations than smaller relatives. We use a biogeographical and morphological method to examine degree of taxonomic divergence, degree of local species radiation, and incidence of apparent extinction in the East Pacific, West Atlantic, and East Pacific zoogeographic subregions for lineages of stomatopods with relatively complex or simple social behavior. We hypothesize that lineages with complex behavior have more endemic species, fewer cognates, and fewer conspecifics among these subregions than lineages with relatively simple social behavior; that lineages with complex behavior undergo more local species multiplication than lineages with relatively simple behavior; and that extinctions are more frequent in species with more complex than simple behavior. However, species that occupy coarse substrates and have associated complex behavior and morphology do not diverge, multiply, or become extinct significantly faster than expected. Similarly, larger taxa do not evolve more rapidly than relatives of smaller body size. Instead, rates of divergence and speciation are significantly inversely related to body size and larval dispersal potential. Although stomatopods show some of the most complex behavior known in invertebrates (with the possible exception of the cephalopods), this behavioral sophistication does not appear to be a predominant force molding the pace of evolutionary change in these marine crustaceans.