Aim. To assess the impact of an intervention aimed to build capacity of registered nurses to enhance the clinical learning environment for undergraduate nursing students. Workplace learning is vital for the development of skills, attributes and knowledge of student nurses. Registered nurses need to be appropriately prepared to maximise student learning during clinical placement. Background. The quality of student learning during clinical practicum is largely dependent on interactions with ward staff. Design. A quasi-experimental design. Method. Measurement of students' perceptions of the psycho social learning environment during and outside of the intervention period was used to evaluate the capacity building intervention. The capacity building intervention consisted of interactive education in clinical areas over a six-week period for registered nurses in two acute surgical wards. Results. First, second and third year students (n = 62) who undertook their clinical practicum in the two surgical wards, before, during and six months after the capacity building intervention assessed the psycho-social learning environment at the time of their clinical practicum. Findings showed that students who undertook their clinical practicum during the intervention period rated the psycho-social clinical learning environment significantly higher than students who undertook their practicum at times outside of the intervention period. Conclusions. An experienced researcher/educator conducting capacity building sessions can effectively assist and support registered nurses to engage with students. Relevance to clinical practice. Capacity building sessions can improve practice, however, structures and processes that ensure continuation of practice change need to be embedded for improvements to be sustained.