The precise nature of attachment to pets and differences between girls' and boys' relationships at age 11, 13 and 15¿years are investigated in this paper. Data from the 2010 Health Behaviour in School-aged Children (HBSC) survey in Scotland were used to examine various qualities of adolescents' attachments to their pet dogs, cats and small mammals. Survey participants (N¿=¿2472) answered pet ownership questions and completed the ‘Short Attachment to Pets Scale’ (SAPS). Multivariate analysis revealed main effects of age, sex and pet type, but no interaction effects. There is a pattern of weakening attachment to pets with increasing age, with emotional support qualities of attachment receiving higher ratings from girls, and stronger attachments evident with dogs. These findings enhance understanding of the role played by pets in the broader relational context of adolescents' lives, and help to identify how we might intervene to support adolescents experiencing socio-emotional difficulties or life disruptions.