This study tested the psychometric properties of the Parent Satisfaction Scale (PSS), a new scale measuring parents' satisfaction with their child's mental health services, primarily focusing on staff's interpersonal interactions. Data were collected by postal surveys 5 to 10 months after a child's admission to 1 of 5 mental health treatment programs. Completed surveys were received from parents of 120 of a potential 232 children (52% response rate). Internal consistency reliability of the PSS was strong (alpha = .96). Construct validity was supported by significant relationships between the PSS and constructs considered to be antecedent variables influencing parent satisfaction, including met expectations (r = 0.62, P < .001), met desires (r = 0.32, P < .001), and met needs (r = 0.55, P < .001). Convergent validity was supported, with the PSS having Pearson correlations of .86 (P < .001) with the Client Satisfaction Questionnaire-8 and .76 (P < .001) with parents' ratings of satisfaction with specific services received.