One or both sexes exhibit territorial behavior in all dendrobatids that have been studied. Two types of territoriality are identified. In some Colosthethus species only females or both sexes defend small nonreproductive territories that offer access to water, food, and shelter. In other species, only males defend large reproductive territories against conspecific calling males, suggesting that females are the limited resource. However, in no case has the defended resource been unambiguously identified. I hypothesize that, in at least some species, males compete for calling sites in areas with high female density and with favorable sound transmission features. I found little support for the hypothesis that dendrobatids exhibit resource defense polygyny. More research is necessary to understand the function of territoriality and to identify limiting resources in poison frogs.