The Triple P Positive Parenting Program is a multilevel system of behaviour-based parenting training and support. The aim of this study was to determine whether implementation of levels 2 and 3 of the Triple P system, designed for primary care settings, enhances parent, child and family outcomes compared with services-as-usual in Alberta, Canada. The study employed a quasi-experimental, single-blind and post-test-only design. A survey incorporating outcome measures was administered to a sample of 1296 parent-clients. A total of 923 parents responded, including 172 parents who had received a Triple P (level 2 and/or 3) intervention during the previous 12 weeks. A significant interaction was found between participation in a group-based parent education programme and receipt of Triple P. Parents who participated in a group-based parent education programme, and who received a Triple P intervention reported somewhat higher levels of need satisfaction than parents who participated in a group-based parent education programme but who did not receive a Triple P intervention. No significant difference was found between Triple P and service-as-usual groups on any secondary outcome measures including parenting stress, positive interaction, family functioning and child problem behaviours.