This paper acknowledges the critical importance of effective practice learning experiences within pre-registration nursing programmes and recognises that such student experiences are commonly delivered by use of a block or integrated practicum framework. It highlights a paucity of research regarding the most effective model to facilitate positive placements and optimise learning before reviewing a range of theories that may act as underlying causative mechanisms affecting clinical experiences for such learners. Congruent with Critical Realist principles, a realist synthesis is undertaken to identify theories and associated empirical studies which might best explain the most important factors affecting practice learning placement within pre-registration nursing programmes. Five theoretical concepts derived from the literature search appear relevant for further examination in respect of their effect on the most desirable practicum model for nursing students; namely the ‘Distributed Practice Effect’, ‘Contextual Interference Effect’, ‘Situated Learning Theory’, ‘Social Identity Theory’ and the ‘Theory of Human Relatedness’. These concepts are explained, supported by related research and their potential relationship with the most desirable qualities of a nursing student placement outlined. It is so far unclear as to the precise extent these five concepts support use of the block and integrated practice learning models within pre-registration nursing programmes; although preliminary analysis suggests the Theory of Human Relatedness may provide the most complete theoretical framework to explain student practicum experiences. The author hopes this realist synthesis will stimulate wider academic debate on the subject and encourage further research in the field.