We describe the long-term regeneration dynamics of the maritime holly forest, a plant community restricted to two known locations on Atlantic barrier islands: the Sunken Forest, part of Fire Island National Seashore, New York, and the Sandy Hook holly forest, part of Gateway National Recreation Area, New Jersey. In order to assess the short-term changes in vegetation apparent at one location, we examined the long-term dynamics of these two forests. Analysis of permanent plots in the Sunken Forest indicated the overstory structure and composition had changed minimally, but the understory decreased in cover and diversity over a period of 35 years (1967–2002). Patterns differed at Sandy Hook, with little change in the forest understory evident in permanent plots monitored over a period of 14 years (1989–2003). The age distributions indicate that both forests are uneven aged, but the trees at the Sunken Forest are older than those at Sandy Hook. While there has been an overall lack of establishment of any species since the 1970s at the Sunken Forest, several stems were present in the smallest age and size classes within the Sandy Hook holly forest. Release patterns in the tree cores reveal responses to frequent moderate disturbances including hurricanes, tropical storms, and northeasters. No recent changes in the frequency of canopy disturbances were evident in the tree core analysis, but herbivory has likely increased with the dramatically rising Odocoileus virginianus population at the Sunken Forest since the 1970s. The maritime holly forest relies on new individuals establishing in openings created by moderate disturbances; the current high level of herbivory at the Sunken Forest is disrupting the long-term regeneration patterns of this critically imperiled maritime holly forest.