Coastal forests and wetlands play an important role in supporting biological diversity, protecting the hinterlands and shorelines along the continental margins from erosion, as well as for contributing to carbon and freshwater storage. To reconstruct late Holocene vegetation and environmental dynamics in the coastal lowlands in northern Iran and detect the possible role of climate, human impact and Caspian Sea (CS) level fluctuation on coastal ecosystems, a multi-proxy analysis including pollen, spores, non-pollen palynomorphs, macro-charcoal and X-ray fluorescence analysis, have been applied on the radiocarbon dated sediment cores from the Eynak (EYK) lagoon further inland and Bibi Heybat (BBH) alder swamp near the coast. Open wetlands covered relatively large areas since the recorded period (1450 cal yr BP). At BBH larger areas of open vegetation occurred and alder forests covered only small areas that expanded during the late Little Ice Age (1650-1850 AD) and were most abundant during the last about 100 years. Further inland at EYK, areas of alder and mixed broad-leaved Hyrcanian forest were larger. Alder forest in general expanded since 600 cal yr BP. In the last 170 years, alder forest areas and wetlands declined strongly, due to deforestation and strong human activities. The intensity of human impact, climatic fluctuations and changes in CS level were the most important factors controlling the dynamics of the northern Iranian coastal vegetation.