The popularity of assigned or forced same-gender and cross-gender matches between school mentors and student teachers has heightened concerns regarding the ethical and/or unethical behaviours of mentors. In this article the authors present the findings of a cross-sectional survey study on the prevalence of ethical and/or unethical behaviours of school mentors in forced same-gender and cross-gender matches from the perspective of their student teachers in Malawi's Initial Primary teacher education mentoring programme. The study was grounded in a positivist paradigm and a quantitative approach was followed. A structured questionnaire was dropped to and picked up from a census sample of 616 student teachers who were attached to 92 school mentors in 92 primary schools by one of the Primary teacher training colleges in Malawi. Univariate and bivariate analysis using SPSS version 20.0 was employed to analyse the quantitative data. The results revealed that school mentors in forced same-gender as well as in cross-gender matches exhibited more unethical than ethical behaviours to their student teachers; and that their unethical behaviours were graver in demonstrating deontological responsibility such as using their power and authority to expose student teachers to risky conditions. The study also found no significant difference in ethical and/or unethical behaviours of mentors in forced same-gender and cross-gender matches. Overall, the results supported the need for careful mentor selection; regular mentor development opportunities; and regular monitoring of the mentoring processes.