This paper sought to describe the combined influences (confluence) of the various aspects of the supplemental instruction (SI) programme on selected student outcomes. It points out that the SI programme’s influence goes beyond the reports about the improvement of marks, throughputs, and retention. It shows that the SI programme bears on the development of academic literacies, graduate attributes, the building of a sense of community, and the inculcation of ethos and practices necessary for academic success. Framed in the positivist paradigm and a quantitative approach, aspects of the supplemental instruction programme such as instructional methods, lecturer’s attitude towards SI, accessibility of the SI leaders, lecturer and departmental involvement, and student–facilitator relationship were correlated with the variables of students’ outcomes. The students’ outcome variables were measured by the acquisition of academic literacies and competencies, improved performance in assessment tasks, sense of community and belonging, and assimilation into a university’s culture and ethos. Using purposive/convenient sampling, 122 students who made extensive use of the SI programme were selected to participate in a survey. Data were analysed statistically using ordinal regression. The study’s findings highlight the need to consider different constructs in the planning and implementation of the SI programme. It provides evidence of students’ successful engagement with supplemental instruction and the factors that contribute to such success. This study helps foster an understanding of the various planning, design, and delivery aspects of the supplemental instruction programme, so that ways of making the SI programme effective are devised. The identified significant factors form the basis for the construction of an SI implementation conceptual framework.