Syria’s health professionals have been displaced to neighbouring countries including Jordan and Lebanon since the devastating civil war began in 2011. Our mixed-methods research focused on Lebanon, exploring the emerging phenomenon of qualified Syrians carrying out informal healthcare work to meet local needs. We found a diverse workforce practising in the informal sector, predominantly in primary care settings and as volunteers. But interviewees reported living in fear of exposure and experience wage discrimination in comparison with locals. We recommend that the Lebanese government consider limited registration for Syrian healthcare workers — enabling them to deliver services formally to Syrian refugees — and that donors radically expand the scale and scope of their support for education and training initiatives in the region to prevent the generational gap in the Syrian health workforce from growing.