The need for effective training methods for enhancing cognitive‐behavioural therapist competency is not only relevant to new therapists but also to experienced therapists looking to retain and further enhance their skills. Self‐practice/self‐reflection (SP/SR) is a self‐experiential cognitive‐behavioural therapy (CBT) training programme, which combines the experience of practicing CBT methods on oneself with structured reflection on the implications of the experience for clinical practice. In order to build on previous qualitative studies of SP/SR, which have mainly focused on trainee CBT therapists, the aim of the current study was to quantify the impact of SP/SR on the therapeutic skills of an experienced cohort of CBT therapists. Fourteen CBT therapists were recruited to participate in an SP/SR programme specifically adapted for experienced therapists. In the context of a quasi‐experimental design including multiple baselines within a single‐case methodology, therapists provided self‐ratings of technical cognitive therapy skill and interpersonal empathic skill at four critical time points: baseline, pre‐SP/SR and post‐SP/SR and follow‐up. Analysis of programme completers (n = 7) indicated that SP/SR enhances both technical skill and interpersonal therapeutic skill. Further intention‐to‐treat group (n = 14) analyses including both those who left the programme early (n = 3) and those who partially completed the programme (n = 4) added to the robustness of findings with respect to technical cognitive therapy skills but not interpersonal empathic skills. It was concluded that SP/SR, as a training and development programme, could offer an avenue to further therapeutic skill enhancement in already experienced CBT therapists. Copyright © 2014 John Wiley & Sons, Ltd. Key Practitioner Message It was possible to quantify the positive impact of a self‐practice/self‐reflection (SP/SR) training and development programme within a cohort of experienced cognitive‐behavioural (CBT) therapists. Through SP/SR, experienced CBT therapists can further enhance their self‐perceived therapeutic skills in two key domains; technical cognitive therapy skills and interpersonal empathic skill. Further SP/SR studies should aim to incorporate objective measurement of therapeutic skill, ideally from more than one rating source.