This study aims to validate the Bullying and Cyberbullying Behaviors Questionnaire, to examine the prevalence of bullying and victimization behaviors in Portuguese middle school students, and to analyse the differences in victimization and bullying between genders and across school grades. The questionnaire is composed of 36 items, allowing for the measurement of the prevalence of bullying and cyberbullying, and was completed by 1,039 sixth to eighth graders (M[subscript age] = 12.02; SD = 1.36) from six public middle schools in the district of Lisbon. The questionnaire presented acceptable psychometrics properties, except for the victims of cyberbullying scale where there is an item that needs to be rewritten. Bullying prevalence (10.1% victims and 6.1% aggressors) is among the lowest internationally. Victimization prevalence was homogeneous between genders, but boys reported aggressive behaviors more frequently. The percentage of victims decreased across school grades. The present questionnaire is adequate for use in the assessment of bullying and cyberbullying with middle school students. Bullying prevention programs should take into account the need to raise teacher awareness of bullying and cyberbullying.