Despite Kenya Government's commitment to enhancement of girl-child education, their participation rate at secondary school level is still notably low. Many studies on the girl-child education have concentrated in the rural populations with the assumption that the situation in the urban setting is nearly ideal. This was not the case as was evidenced in the period 2004-2007 whereby, mixed day secondary schools in Kisumu Municipality were averagely made up of only 43% girls. Headteachers as implementers of government policies are well placed to enhance girl child participation in mixed day secondary schools. The purpose of this study was therefore to investigate the opportunities, challenges and coping strategies for headteachers in the promotion of secondary school girl-child education. The findings of the study were that headteachers had several opportunities such as financial resources, government policies, political goodwill, personnel and facilities to promote girl-child participation in secondary education. Headteachers faced challenges including indiscipline, inadequate facilities and personnel, poverty and girl-child drop-out. Strategies to cope with the challenges were government policies, parental involvement and availing resources and personnel for the girl-child education. Based on the findings, the study recommended that the government should formulate appropriate educational policies whose implementation would be monitored and evaluated to improve Girl child education. Besides, the headteacher should facilitate the affordability of girl-child education in mixed day secondary schools. (Contains 3 tables and 4 figures.)