This paper outlines a recently designed programme of training for graduate teaching assistants (GTAs), focusing on peer elements embedded in the programme. In particular, we describe our approach to co-facilitation of training, with sessions facilitated by the GTA programme lead and an experienced Peer GTA. Peer GTAs have at least one year of teaching experience and are able to provide practical, contextualised and discipline-specific input, which helps to address the challenge of balancing generic and discipline-specific training in GTA programmes. We describe a small case study of co-facilitation and reflect on the benefits of this approach for new GTAs and for the Peer GTAs themselves. The paper is co-authored by the GTA programme lead and a Peer GTA, who provides first-hand reflections on her experiences.