Adolescents spend an increasing amount of time using digital media, but gender differences in their use and in associations with psychological well-being are unclear.We drew from three large, representative surveys of 13- to 18-year-old adolescents in the U.S. and UK (total N = 221,096) examining digital media use in hours per day and several measures of psychological well-being separately in each of the three datasets.Adolescent girls spent more time on smartphones, social media, texting, general computer use, and online, and boys spent more time gaming and on electronic devices in general. Associations between moderate or heavy digital media use and low psychological well-being/mental health issues were generally larger for girls than for boys. Light users of digital media were slightly higher in well-being than non-users, with larger differences among boys. Among both genders, heavy users of digital media were often twice as likely as low users to be low in well-being or have mental health issues, including risk factors for suicide.Associations between heavy digital media use and low psychological well-being are larger for adolescent girls than boys.