Most traumatic brain injury (TBI) cases are considered mild. Precise definitions vary, but typically, loss of consciousness and post-traumatic amnesia duration is brief (e.g. <30 minutes and <24 hours respectively), and standard imaging is normal. Prognosis in mild TBI is generally good, but disabling persistent symptoms such as headaches, dizziness, affective and cognitive issues are common. A focussed assessment tailored to each individual symptom is crucial for management. Advanced MRI and blood-based biomarkers of mild TBI are emerging and are likely to play an increasingly important role in the assessment of patients following a head injury.