Myalgic encephalomyelitis, also known as Chronic Fatigue Syndrome, is a deeply complex and multi-system condition which has historically suffered from a lack of awareness within physiotherapy education and practice. Similarities in presentation between this condition and Long Covid make this comprehensive and evidence-based guide for physiotherapists even more timely and important. This guide includes an in-depth explanation and history of ME/CFS whilst also describing symptoms, varying degrees of severity, and how to manage ME/CFS in children. It also provides detailed management advice and discussion on how the information can directly inform physiotherapy practice, supplemented with patient case studies.