This paper uses British and Canadian linked employer-employee data to investigate the importance of the workplace for the gender wage gap. Implementing a novel decomposition approach, we find high levels of unexplained wage inequality in the private sector of both countries, which is related to women receiving relatively lower wages within workplaces than do men. Whilst this inequality is partially offset by women, on average, receiving a workplace specific return which is relatively higher than that paid to men, a substantial and significant unexplained within workplace wage gap remains which is considerably higher in Britain than in Canada. The results are consistent with a prima facie argument that country-specific factors, such as the wage setting environment, are important determinants in explaining the relative size of the gender wage gap.