The outbreak of COVID-19 and the consequent lockdown took the world by surprise, forcing the trimming of the school curriculum and institutions of higher learning to urgently adopt online platforms to continue teaching and learning. This article is a case study that explores the use of a social media platform, WhatsApp, to improve peer learning and peer support in a South African context. The study sought to explore the nature of peer-to-peer learning that took place, and how peer support contributed positively to a student's conceptual understanding of the mathematics concepts. It involved a cohort of 180 entry-level students of an undergraduate engineering mathematics course. Guided by social constructivism, we analysed the data qualitatively using grounded theory. The results suggest that WhatsApp served as a viable platform for communication and peer-to-peer learning of engineering mathematics concepts. The study also found that the WhatsApp postings peer support alleviated the negative effects of remote learning. Some implications of the study as well as recommendations are suggested.