Our systematic review and meta-analysis protocol was developed according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) statement. The protocol for this review has been registered in the PROSPERO network (registration number: CRD42017076628). This systematic review and meta-analysis of the incidence of MH in patients undergoing general anesthesia will be performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines and will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines.