For nearly 20 years trade officials and scholars debated whether a national measure restricting trade on the basis of animal welfare concerns could be deemed compliant with the rules of the World Trade Organization (WTO). In June 2014, the dispute settlement body of the WTO adopted the decision on the EC - Seal Products case confirming that trade-restrictive measures aimed at safeguarding the welfare of animals can be deemed necessary to protect citizens' moral concerns. While this decision provides long-awaited answers and insights, it does not exhaust the debate on the obstacles for justifying animal welfare trade restrictions. This paper provides an overview of controversies surrounding the topic of animal welfare from a WTO perspective and a brief review of the findings from the EC - Seal Products case. In addition, this chapter calls for further research on potential controversies that may rise in relation to trade measures in contexts beyond seal hunting; like, for instance, regulatory divergences over farm animal welfare measures. In doing so, it recommends that future research pays special attention to the potential controversies associated with the use of animal welfare recommendations elaborated by the World Organisation for Animal Health (OIE) (OIE, 2019).