For over half a century, one pillar of the world trading system has been the principle of ‘special and differential treatment’ (SDT) for developing countries. This column explores how SDT has impacted trade policy around the world. Although this strategy aims to help developing countries, in design and practice it seems to be biased against them. While there is no support for SDT as a growth-promoting strategy, there is a clear need for further research that explicitly tackles the empirical challenges that it presents.