In industrialized countries, teenagers are likely to engage in consumerism given the influence of the media and their peers. Consumer behavior is often irrational, as shown by research on impulse buying. Impulse buying tendency (IBT) is characterized by hedonic shopping motivation, materialism and need for cognition (NC). We hypothesize (1) that hedonism mediates the relationship between materialism and IBT; (2) a negative correlation between NC and IBT; (3) that NC moderates the relationship between hedonism and IBT, as well as between materialism and IBT. We will collect data from six countries with participants being adolescents 13–18 years old.