Self-Practice/Self-Reflection (SP/SR) has been developed as a self-experiential training strategy to enhance CBT therapists’ skills. SP/SR gives therapists an experience of CBT through practising CBT techniques on themselves, and reflecting on the experience and its implications for clinical practice. Many practitioners report significant professional and personal gains from SP/SR; however, there is considerable individual variation. This study examined individual experiences of SP/SR in order to develop a better understanding of idiosyncratic variations in participants’ approaches to SP/SR, and to inform the design and implementation of future SP/SR programmes. A single-case design was employed to examine the experiences of four trainee cognitive-behaviour therapists who were undertaking SP/SR as part of their professional training in CBT. Quantitative data from self-ratings of skill, and qualitative data from participants’ reflections and attributions following completion of SP/SR were examined. Both the participants, and two additional reviewers were consulted in the interpretation of the results. The impact of SP/SR appeared specific to each participant, reflecting different ways that participants engaged with SP/SR materials. The study suggests that for optimal development, engagement of the personal self and therapist self may be required.