The objectives of the present study were to assess the effects of online cognitive behavioural therapy (CBT) training for therapists on measures of CBT knowledge, skills, confidence, and utilisation; to determine what differences might exist between a group supported by regular telephone contact and an independent group who undertook online training without additional support; and to determine the acceptability of CBT online training among rural and remote mental health professionals. Mental health practitioners were randomly allocated to a supported training group (six sessions of 15-min support) or an independent group. They undertook a 12-week online CBT training program. The two groups showed similar gains on an objective test of knowledge of CBT, and on self-report measures of knowledge, skills, confidence levels, and utilisation of skills. However, the supported training group had a significantly higher program completion rate than the independent group. Participants evaluated the program favourably. The results suggest that online CBT training represents a promising and cost-effective approach to training the mental health workforce, and may be particularly attractive for those who live in regional, rural, and remote communities. A challenge is to determine the most cost-effective ways to enhance program completion rates and trainee skills.