Motivational interviewing (MI) is an evidence-based intervention that has been widely recommended in clinical settings where consumer behaviour change is a goal of treatment. Training clinicians in MI, as with other translational endeavours, does not always result in changes to clinical practice. The present study compares two post-training approaches to consolidate MI skills following a training workshop. We randomly assigned 63 clinicians working in mental health or drug and alcohol services to receive either face-to-face group consolidation sessions or to access a series of online consolidation resources. We compared clinician engagement and devised a new instrument to measure clinician outcomes. Participants who completed follow-up consolidation retained knowledge, attitudes, and practices, regardless of consolidation method. Face-to-face consolidation sessions were superior to online materials in engaging participants (mean sessions attended was 2.1 (maximum possible = 3) compared to a mean of 1.38 sessions, respectively (t(61) = -2.73, P = 0.008, d = 0.72, 95% confidence interval: 0.19-1.25). Engagement to the completion of consolidation sessions was also influenced by previous training in MI. For every additional hour of previous MI training, there was a 10% increase in the odds that the participant would complete the final consolidation session.