Introduction The perceived capacity to perform particular activities or skills (i.e. self-efficacy) is paramount in occupational therapy and is thought to be reinforced by actual functional capacity. This study examined whether changes in self-efficacy or confidence to lift weighted items influences changes in occupational performance and disability levels in patients attending a cognitive behavioural therapy pain management programme. Method Clients attending an 8-week cognitive behavioural therapy pain management programme ( N = 125) completed questionnaires before treatment, at discharge, and at 3-month and 6-month reviews, including measures of pain self-efficacy, disability and self-perceived performance and satisfaction using the Canadian occupational performance measure. Analyses examined disability and occupational performance over time, adjusting for baseline characteristics (age, sex, education), and sought to determine whether self-efficacy or lifting confidence influenced the outcomes. Results The level of disability, lifting confidence, self-efficacy and occupational performance all improved over time; however, only occupational performance and lifting confidence maintained improvements up to the 6-month review. Self-efficacy had a greater impact on occupational performance than lifting confidence.