The social networks of students, and the underlying processes of selection, can have strong effects on their psychological and academic adjustment. The effects of gender, friendship aim (intimacy or social activities) and the combination of gender and friendship aim on selection patterns (student's activity in selecting new friends, linking with friends of friends, and similarity in behavior) were studied, using two wave data from 741 students (12-14 years old) in 27 freshmen classes in Dutch high schools.Many students did not fit the gender-typical expectations regarding friendship aim (girls preferring intimacy and boys social activities). In most classes, girls who preferred intimacy, and boys who preferred social activity, were more active in engaging in new friendships than the other girls and boys. Girls who preferred intimacy more often befriended classmates who were similar in school behaviors, whereas boys who preferred social activities more often befriended dissimilar classmates. We discuss these findings with regard to their implications for academic adjustment in terms of academic performance and wellbeing.