Helmets are mandatory for motorcycle riders in all European Union countries.
EU countries also require helmets for all moped, scooter and motorcycle riders.
Belgium, the Czech Republic and the Netherlands allow for some flexibility in helmet laws for drivers of mopeds meeting certain conditions. In Belgium, the mopeds must not exceed 25 km/h; in the Czech Republic, they must not exceed 40 km/h; in the Netherlands, they must not exceed 20 km/h.
Greek and Italian law enforcement may not pull you over for not wearing a helmet. However, you are required to wear one in these countries. In addition, any insurance you have may be rendered invalid if you don't wear one.