Background and aims: Skin gambling uses in-game items (skins) acquired in video games, to gamble on esports, games of chance, other competitive events and privately with friends. This study examined characteristics of adolescent skin gamblers, their engagement in monetary gambling, and relationships between skin gambling and at risk/problem gambling. Methods: Two samples of Australian adolescents aged 12-17 years were recruited to an online survey through advertisements (n 5 843) and an online panel provider (n 5 826). Results: In both samples, past-month skin gamblers (n 5 466 advertisements sample; n 5 185 online panel sample) were more likely to have lower wellbeing, score as having an internet gaming disorder on the IGD, engage in more types of monetary gambling, and meet criteria for problem gambling on the DSM-IV-MR-J. Past-month skin gambling uniquely predicted problem gambling when controlling for past-month gambling on 11 monetary forms and the total number of monetary gambling forms. Discussion and conclusions: Underage participation in skin gambling is a growing concern. The strong convergence between engagement in skin gambling and monetary gambling suggests common risk factors may increase the propensity of some adolescents to gamble on these multiple forms. Nonetheless, past-month skin gambling predicted problem gambling even when controlling for past-month monetary gambling, indicating its unique contribution to gambling problems and harm. While the study was based on non-probability samples, its results strengthen the case for regulatory reforms, age restrictions and public health education to prevent underage skin gambling and its potentially harmful consequences for children and young people.  Kulcsszavak: in-game items, skin betting, video games, loot boxes, gambling disorder, youth