PurposeScience, technology, engineering, mathematics and medicine (STEMM) workplaces worldwide remain stubbornly resistant to gender equality initiatives. Leaders are vital to driving change, but the extent to which their capabilities lead to change remains unknown. This article examines STEMM leaders' gender competence to achieving transformative changes in gender inequality.Design/methodology/approachThis article examines the capability of STEMM leaders to act as change agents through an in-depth, qualitative analysis of perceptions of gender inequality, sexual harassment, sex discrimination and gender bias within their organisations. Findings are analysed using a customised tripartite gender competence schema, comprising commitment, knowledge and method (or know-how).FindingsThe findings suggest that while STEMM leaders may express a commitment to addressing gender inequality, misapprehensions about the nature and scope of the problem are likely to hamper efforts. Two key misapprehensions standout: a tendency to frame gender inequality in primarily numerical terms; and recourse to blaming external factors beyond STEMM for gender inequality in STEMM.Originality/valueThis article makes an original contribution by examining the gender competence of leaders in STEMM organisations, which has not been previously researched. The findings extend understanding of the salience of leaders' capabilities to lead change by identifying key gaps and misapprehensions in STEMM leaders' understanding of the nature and scope of the problem.