Original article can be found at: http://www.sciencedirect.com/ Copyright ElsevierDespite the proven effectiveness of helmets in avoiding or reducing the severity of brain injuries and the law requiring their compulsory use, both by drivers and passengers of motorcycles, approximately 20% of Spanish adolescent motorcycle users do not wear them. This study analysed the pattern of motorcycle and helmet-use in a sample of Spanish adolescents (age range 14???17; n = 874) and the relationship this safety measure has with belief in its effectiveness and its use by friends and relatives. Overall more males than females ride motorcycles and this difference increased with age. Motorcycle drivers and passengers who always wear helmets consider them to be more effective than those who do not use a helmet all of the time. The best predictors of helmet-use among motorcycle drivers were their beliefs regarding the helmet-use of their friends and relatives. In the case of passengers, knowing that their friends always wear them and age were the best predictors of helmet-use. Programmes and campaigns promoting helmet-use must take into account the modelling effect of close referents or other role models in order to increase their effectiveness