This study investigated sex differences in mobile telephone, computer, and Internet use and attitudes via self-report questionnaires in 15 and 16 year olds. Significant sex differences were reported for use and computer anxiety, and use and Internet attitudes, although both females and males were generally competent and frequent users of both technologies. No sex differences were reported for either general mobile phone use or expertise, although analysis of specific aspects of use indicated that the sexes favored different phone activities.