Phenomenon: In the United Kingdom (UK) the government has increased the number of places at university to study medicine in England to meet workforce demands. In parallel, there have been growing student numbers in other healthcare professions and new professions whose roles overlap with doctors, such as advanced nurse practitioners and physician associates, have been introduced. These increasing numbers of medical students and other healthcare professions training in the same clinical setting have led to questions about the effect on the student experience. We aimed to investigate the impact of student-student encounters on the learning experience during clinical placements before student numbers increase further. Approach: In this investigation medical student perceptions were collected retrospectively at Norwich Medical School, University of East Anglia in the UK, during the 2018/19 academic year following two clinical placements in secondary care settings. Through mandatory online course evaluations, all medical students were asked if their learning had been positively or negatively affected by other students, and how frequently they had certain student-student experiences. Findings: Responses from 786 (of 844) medical students (93% response rate) demonstrated that most students felt their learning had been affected in some way by the presence of others while on their secondary care placements. Students experienced both positive and negative impacts of encounters with other students. Final year students tended to report more negative experiences, with first year students reporting more positive. while some students had experienced competition for learning opportunities and lower quality interactions with patients and doctors due to “overcrowding,” more students reported benefits from learning from and with other students. However, it also was found that any negative encounters with other students, even if accompanied by positive experiences, detrimentally affected student satisfaction with the placement. Insights: This investigation indicates that student-student interactions influence the clinical learning experience of medical students both positively and negatively. Given the overriding influence of negative encounters, the findings suggest a need to maximize the beneficial effects of encountering other students on clinical placements; while protecting against missed or poor-quality learning opportunities due to competition between students, particularly for more senior students. Medical educators need to consider where their clinical attachments are at risk from multiple students being present at the same time and work to alleviate the negative impacts of such student-student encounters, while actively encouraging peer learning experiences between the medical students and collaborative activities between students of different healthcare professions. This is likely to become increasingly important as student numbers in medicine and other healthcare professions continue to grow.