jats:titleAbstract</jats:title>jats:secjats:titleAim</jats:title>jats:pSeasonally dry tropical forest (<jats:styled-content style="fixed-case">SDTF</jats:styled-content>) of the Caribbean Islands (primarily West Indies) is floristically distinct from Neotropical <jats:styled-content style="fixed-case">SDTF</jats:styled-content> in Central and South America. We evaluate whether tree species composition was associated with climatic gradients or geographical distance. Turnover (dissimilarity) in species composition of different islands or among more distant sites would suggest communities structured by speciation and dispersal limitations. A nested pattern would be consistent with a steep resource gradient. Correlation of species composition with climatic variation would suggest communities structured by broad‐scale environmental filtering.</jats:p></jats:sec>jats:secjats:titleLocation</jats:title>jats:pThe West Indies (The Bahamas, Cuba, Hispaniola, Jamaica, Puerto Rico, US Virgin Islands, Guadeloupe, Martinique, St. Lucia), Providencia (Colombia), south Florida (<jats:styled-content style="fixed-case">USA</jats:styled-content>) and Florida Keys (<jats:styled-content style="fixed-case">USA</jats:styled-content>).</jats:p></jats:sec>jats:secjats:titleTaxon</jats:title>jats:pSeed plants—woody taxa (primarily trees).</jats:p></jats:sec>jats:secjats:titleMethods</jats:title>jats:pWe compiled 572 plots from 23 surveys conducted between 1969 and 2016. Hierarchical clustering of species in plots, and indicator species analysis for the resulting groups of sites, identified geographical patterns of turnover in species composition. Nonparametric analysis of variance, applied to principal components of bioclimatic variables, determined the degree of covariation in climate with location. Nestedness versus turnover in species composition was evaluated using beta diversity partitioning. Generalized dissimilarity modelling partitioned the effect of climate versus geographical distance on species composition.</jats:p></jats:sec>jats:secjats:titleResults</jats:title>jats:pDespite a set of commonly occurring species, <jats:styled-content style="fixed-case">SDTF</jats:styled-content> tree community composition was distinct among islands and was characterized by spatial turnover on climatic gradients that covaried with geographical gradients. Greater Antillean islands were characterized by endemic indicator species. Northern subtropical areas supported distinct, rather than nested, <jats:styled-content style="fixed-case">SDTF</jats:styled-content> communities in spite of low levels of endemism.</jats:p></jats:sec>jats:secjats:titleMain conclusions</jats:title>jats:pThe <jats:styled-content style="fixed-case">SDTF</jats:styled-content> species composition was correlated with climatic variation. <jats:styled-content style="fixed-case">SDTF</jats:styled-content> on large Greater Antillean islands (Hispaniola, Jamaica and Cuba) was characterized by endemic species, consistent with their geological history and the biogeography of plant lineages. These results suggest that both environmental filtering and speciation shape Caribbean <jats:styled-content style="fixed-case">SDTF</jats:styled-content> tree communities.</jats:p></jats:sec>