This paper examined the School-Based Management Committee's (SBMC) involvement and effectiveness in school governance, curriculum implementation and students' learning outcomes in Nigerian secondary schools; the major challenges facing effective operation of SBMCs were identified as low capacity of key members of the SBMCs; poor attendance of members at meetings due to lack of incentives and financial support from the government; lack of cooperation from the schools; and PTA's resistance to the SBMC initiatives; these resulted in ineffective school management and low level of students' academic achievement. It was concluded that a conceptual model of inter-relatedness be adopted to strengthen the operational capacity of SBMCs for efficient service delivery and quality learning outcomes in secondary schools.