This manual is part of a series produced as a follow-up to UN Resolutions on road safety and World Report on Road Traffic Injury Prevention, which call for addressing key road safety risk factors by UN Member States. Increased motorisation in developing countries entails a rapid growth in the use of two-wheeled vehicles, resulting in increased fatalities and injuries among motorcycle, moped and bicycle riders. Helmets are an effective means of protecting these vulnerable road users, allowing to prevent 40% of fatalities. The manual provides structured step-by-step advice on how to increase the use of helmets within a country, namely, how to start a helmet use programme, how to access the helmet situation in a country, how to design and implement a helmet use programme, including setting up a working group, developing an action plan, introducing and enforcing mandatory helmet laws, creating standards for helmet production, marketing helmets to the public, educating the population on helmet use, etc., and implementing an evaluation of the programme. Throughout the manual case studies from around the world illustrate examples of good practice relating to the use of helmets.