This review provides a brief update of the occurrence and adaptive significance of asexual reproduction in echinoderms. It then focuses on the state of knowledge of biotic and abiotic factors that influence asexual processes in this group, particularly factors that may play a role in regulating the expression and relative proportion of asexual versus sexual phenotypes within populations of species, as well as factors modulating and triggering asexual processes. The information presented in the review is synthesized into the form of a basic model depicting how environmental factors may interact with physiological factors to regulate asexual reproduction in echinoderms, and to show how such regulatory processes may parallel in some ways those known to regulate sexual reproduction. Since the model is based mainly on correlational evidence derived from comparative field observations, a number of experimental approaches for testing the predictions of the model are discussed briefly.