We examined factors that inspire teenagers to comply with cyber security guidelines. We used protection motivation theory (PMT), and extended the model to include personal norms and normative beliefs. For teenage computer users, believing they are susceptible to hacking or that the consequences of being hacked would be severe, had no bearing on their password choices. This is an interesting finding highlighting a potential difference between adults and teenagers. We found personal norms is a better predictor of teenagers’ security behaviour than PMT’s threat perceptions. This is an important finding which opens new avenues for future research, particularly in explaining teenagers’ security behaviour. This study contributes to finding ways to improve security practices at an early age. To the best of our knowledge this is the first password security study that applies PMT to examine security behaviours in teenagers