The vegetation history of the island of Martha's Vineyard, Massachusetts during the last millennium was investigated with particular focus on the occurrence and distribution of coastal sandplain grasslands prior to European settlement. The objectives of the research were (1) to examine by paleoecological methods the possibility that grasslands existed on Martha's Vineyard as a "natural" vegetation type before the introduction of European agriculture, (2) to address the effects of land use, fire, soils, and near-coastal location on the occurrence of grasslands across the island during the last 1000 years, and (3) to provide a historical perspective to grassland dynamics that may be relevant to conservation planning and management. To address these research objectives, 12 sediment cores were collected from Martha's Vineyard and analyzed for pollen and charcoal. Nine cores were recovered from the outwash plain, where coastal sandplain grasslands occur today or are known to have occurred historically, and 3 cores were collected from the moraine of the island. Sediments from multiple cores were analyzed to characterize spatial and temporal vegetation changes across the island that may be related to land-use history, fire occurrence, or soil conditions. Vegetation near study sites was sampled to characterize modern grassland and forested communities and to identify environmental gradients responsible for variations in species abundances. Modern vegetation types were also compared to surface pollen assemblages and analogous prehistoric pollen spectra. Results suggest that sandplain grasslands or associated vegetation types occurred on Martha's Vineyard prior to European settlement, at least in localized areas near coastal ponds on the outwash plain, and that these grassland types probably occurred in response to burning by native American Indians. The importance of prehistoric fire on the island is inferred from higher pre- than post-settlement charcoal content in sediments from most study sites. The near-coastal influences along the island's southern shoreline, where early successional communities occur today, may also have favored grassland vegetation types in the past.