Island biodiversity is unique, characterized by high rates of endemicity, phylogenetic disharmony, and distinctive phenotypes. Island biodiversity is also among the most threatened in the world, accounting for disproportionate numbers of species endangerments and extinctions, and invasive species are identified as a major threat. It has been predicted that island plants have evolved weak competitive abilities as a consequence of low species richness and the relatively mild climates of islands, making them easily outcompeted by more vigorous continental species that naturalize on islands. However, very little direct evidence via competition experiments or demographic analyses has been collected to test this idea. With limited time and resources to study the biology of island species, functional traits offer a compelling approach to investigate whether island plants are generally more conservative in their resource use traits, providing a mechanistic understanding of their potential to compete with acquisitive, fast-growing invasive plants. We propose to develop an open-access database that compiles resource use traits associated with growth strategies of island plants. The database will be global in coverage, including trait data extracted from literature searches using systematic review methods. Oceanic and continental islands will be targeted, but other insular habitats that often lack the extent of isolation necessary for the evolution of island syndromes will not be included. Functional traits associated with above- and below-ground resource use will be compiled, including anatomical, morphological, physiological, and architectural traits of leaves, stems, roots and whole-plant. Novel aspects of our database include explicit incorporation of intraspecific trait variation (when available) and site-level abiotic conditions (climate, soil, elevation), which together with island characteristics (isolation, area, age) will be used to characterize functional trait diversity that accounts for the extensive heterogeneity within and among islands. The ISLETS database complements other databases for continental plant functional traits (e.g. TRY) and for island floras (e.g. GIFT), and will facilitate synthesis of the resource use strategies of island plants for the first time, providing new insights into the evolution of island syndromes, and shedding light on the potential for island plants to resist competitive displacement by invasive species.