© 2016 IOP Publishing Ltd. Laboratory demonstrators play a crucial role in facilitating students' learning in physics subjects. Inspired by the success of peer-led activities, we introduced peer demonstrators to support student learning in first-year physics subjects that enrol students not intending to major in physics. Surveys were administered to 1700 students over 4 years in four subjects to examine student perceptions of how demonstrators assisted them in the laboratory. Scores awarded to peer demonstrators by students were no lower than those awarded to demonstrators traditionally employed in the first year physics laboratory. These latter demonstrators were drawn mainly from the ranks of physics research students. The findings validate the recruitment of peer demonstrators and will be used to inform the recruitment and support programmes for laboratory demonstrators.