Facilitation cascades occur when a habitat-forming species facilitates another habitat-forming species with synergistic effects on biodiversity. This review summarizes the current state of knowledge of facilitation cascades in marine environments, describing (​1​) the geographic distribution of studies documenting facilitation cascades; (​2​) the range of habitats and organisms involved; (​3​) the mechanisms underpinning their establishment; and (​4​) the sources of their spatial and temporal patterns and variability. We synthesize this knowledge to identify ways in which facilitation cascades could be integrated with other ecological theories regarding community assembly and function, and also to explore how they may be integrated into conservation and management strategies. Finally, we identify critical knowledge gaps and future research directions for improving our understanding of the mechanisms regulating the establishment and persistence of facilitation cascades in marine environments.