Many girls are not sent to school in Yemen, despite basic education being free as well as compulsory for all children aged 6-15. Aiming to improve girls' enrollment by increasing parental and community involvement, the Japan International Cooperation Agency (JICA) offered a technical cooperation project in June 2005 called Broadening Regional Initiative for Developing Girls' Education (BRIDGE). Phase 1 of this project ran for three and a half years, piloting a participatory school management model supported by school grants in six districts of the Taiz Governorate in the Southwest of Yemen. To find out how successful this approach has been in a traditional society, the authors of this paper analysed the gender parity index (GPI) of the project's pilot schools. Based on data collected at three points in time (in the initial and final years of the project, and two years after the project's end), their findings suggest that interventions in school management which strongly emphasise girls' education can be effective in improving gender parity rather quickly, regardless of the schools' initial conditions. However, the authors also observe that the pilot schools' post-project performance in terms of gender parity is mixed. While the local government allocated budgets for school grants to all pilot schools even after the project's end, training and monitoring activities were cut back. The authors further observe that the variation in performance appears to be significantly correlated with school leaders' initial perceptions of gender equality and with the number of female teachers employed. These findings point to the importance of providing schools with continuous long-term guidance and of monitoring those which implement school improvement programmes.