This doctoral thesis aims to communicate the results of a study of the involvement of scientific experts in international dispute settlement. The research has aimed to identify the situations that would benefit from expert assistance in dispute resolution, and how best these experts may be used in a case for efficient and effective dispute settlement. Through a study of existing international legal texts, judicial decisions, and, under the aegis of an SNSF project, conducting interviews of judges, counsel and experts themselves, the thesis concludes with recommendations on best practices when participating in disputes that involve complex scientific questions. The study has shown the myriad ways in which experts may be involved in a dispute, often depending on the forum in question. However, a consolidated approach of examining practices in different unrelated fora yields a diverse set of recommendations that could be flexibly applied in different contexts.