Both benthic and planktic dinoflagellates can produce harmful algal blooms. However most of the studies conducted so far emphasized on planktic species. In the present review, we assessed the main ecological factors affecting the population dynamics of bloomforming benthic dinoflagellates, with particular emphasis on Ostreopsis and Gambierdiscus. Based on the basic equation of population dynamics, we mainly focused on growth, predation, mortality, immigration and dispersion. Factors determining the dynamics of benthic dinoflagellate populations are very different from the well-studied case of planktic dinoflagellates. The relative movement of cells and water is the main difference as benthic dinoflagellates depend on a fixed substratum while planktic dinoflagellates depend on a water body. Any alteration in the substratum will affect benthic dinoflagellate populations, as for example the changes in seaweeds concentrations due to predation by sea urchins. We also evaluated the impact of global changes on dinoflagellates bloom occurrence.