This study sheds light on the underrepresentation of women as school principals by analysing which model (organisational or individual) is most identified with the gender differences in the quality of management found in favour of women principals. To do so, this study presents a model for the appointment of school heads in a two-sided market: demand and supply. On the demand side (organisational model), the presence of double standards, with respect to the promotion of women, would imply that higher bars are set for the evaluation of women. Alternatively, on the supply side (individual model), a potential lower self-efficacy perception among women could lead them to self-exclude from managerial positions. In both cases, the findings reveal only highly-skilled females as principals and a gender gap in principal positions. By using the World Management Survey (WMS), data indicate that female principals are associated with higher management quality, which confirms the presence of barriers to female promotion. Exploration of the market side responsible for these barriers found that only the demand side is significant, which signals the double-standard argument. This supports the argument that changes in the principal selection process should be implemented for the maximisation of the available pool of talent.