Aims: This study aimed to determine the psychometric properties of the headspace youth (mental health) service satisfaction scale (YSSS), a 14-item purpose-designed scale for use with adolescents and young adults attending headspace centres, and to examine the level of satisfaction with headspace centre services and the client characteristics that predict this. Methods: There were 21 354 eligible headspace clients who had received more than one service over the 12-month data collection period during 2013–2014, and 12 436 (58%) completed a satisfaction scale. headspace clients could optionally self-complete the satisfaction scale at the beginning of visits 2, 5, 10 and 15. Clients' demographic and clinical characteristics were also recorded. Results: Factor analysis identified a four-factor solution for the scale and internal consistency of the subscales was acceptable to excellent. Satisfaction with headspace was high and increased over time for those who completed the scale multiple times. Several demographic and clinical characteristics predicted the likelihood of completion and level of satisfaction, with younger age shown to be a persistent predictor of lower satisfaction. Conclusions: Client satisfaction with headspace is high and increases with ongoing engagement. Development of the headspace YSSS contributes a new client satisfaction scale with tested psychometric properties for adolescents and young adults engaged in mental health services, providing an essential tool for youth mental health services to routinely evaluate the experiences of young people accessing their services.