Being highly dependent of imported fossil fuels for its electricity generation, Thailand has an ambitious target for the integration of renewable energy in its electricity portfolio. This paper presents the offshore wind resource map of the Gulf of Thailand, with the objective of identifying the potential areas for grid connected offshore wind power development. A coupled numerical mesoscale atmospheric model and a microscale wind flow model, along with long-term global reanalysis climate data, are used to generate high resolution (200 m) wind resource maps at heights of 40 m, 80 m, 100 m, and 120 m above sea level. The offshore wind resource maps are validated using measured wind speeds obtained from 28 meteorological towers installed along the coast of the Gulf of Thailand. The site selection of potential areas for offshore wind power development is assessed with a multi-criteria decision making analysis. Specifically to the Bay of Bangkok, results show that a technical power potential in the order of 3000 MW could be developed to generate an annual energy production estimated in the order of 6 TWh/year. For the whole Gulf of Thailand, a technical power potential estimated at 7000 MW could generate in the order of 15 TWh/year. (C) 2015 Elsevier Ltd. All rights reserved.