The accession negotiations of Belarus to the WTO are unusual since, due to its obligations in the Eurasian Economic Union, WTO accession is not expected to impact its tariffs or formerly substantial trade‐distorting agricultural subsidies. Nonetheless, we estimate that WTO accession will increase welfare by 9.9% of consumption in Belarus. We show that inclusion of: (i) foreign direct investment; (ii) reduction in non‐discriminatory barriers against services providers; and (iii) our model with imperfect competition and endogenous productivity effects together produce estimated gains eleven times larger than a model of perfect competition with only cross‐border trade in services. Our analysis is enabled by our production of a data set on both discriminatory and non‐discriminatory barriers in services and their ad valorem equivalents. Based on a new data set on labour productivity by sector and type of ownership, in our central model, we estimate that privatisation will increase welfare by 35.8% of consumption. We find substantial variance in the estimated gains from privatisation depending on model assumptions, but all the estimates of the impacts of privatisation indicate substantial welfare gains.