Background: Informal caregivers of patients with amyotrophic lateral sclerosis experience increased levels of caregiver burden as the disease progresses. Insight in the factors related to caregiver burden is needed in order to develop supportive interventions. Aim: To evaluate the evidence on patient and caregiver factors associated with caregiver burden in amyotrophic lateral sclerosis informal caregivers. Design: A systematic review. Data sources: Four electronic databases were searched up to 2017.