Since 1998, non-state actors have had access to submit an ‘amicus curiae’ brief to the WTO DSM. Like other forms of non-state actor involvement in the WTO, amicus curiae access has been controversial. Despite this controversy, non-state actors have made use of this access and submitted amicus curiae briefs. This article asks: What has come of these briefs once they are submitted and what explains how amicus are treated by the DSM? This article empirically maps amici in all disputes from 1998 (after amicus access was first recognized) through 2014, arguing that amicus access is conditioned by a combination of political and legal constraints faced by the WTO panels and AB. In particular, whether the content of an amicus is considered hinges on it having the endorsement of a disputing party and whether its consideration interferes with the WTO DSM's reputation for coherence. In all, these findings have implications for the debate over whether amicus curiae access is good or bad news for the WTO and non-state actor involvement.