The way in which the concept of expertise has been investigated in interpreting studies reflects to a large extent the evolution of the discipline on the whole: from individual reflections ad theories, to empirical studies with different cognitive and linguistic approaches, and, finally, the inclusion of the sociological dimension of the profession. This special issue on Expertise in Conference Interpreting includes six papers which focus on some sociocultural, cognitive and linguistic aspects that are connected to the concept of expertise in conference interpreting.