Purpose of this study was to examine the effectiveness of secondary school principals in discharging their administrative duties in secondary schools in Masaba Division, Kisii Central District, Kenya. The study focused on the management of curriculum and instruction, human and financial resources and school-community relationships. The study was premised on Max Weber Scientific management theory which refers to red tape rigid application of organizational policies while ignoring the workers needs. A descriptive survry research design was used in Masaba Division in Central Kisii District. The study employed purposive sampling to select 8 principals, 8 deputy principals, 40 heads of departments and 40 teachers to yield a sample size of 96 subjects. The main research instruments were different sets of questionnaires to generate quantitative data. The data was analyzed using descriptive statistics. The major findings were that principals had a fairly good mastery of requisite knowledge and skills for curriculum supervision although they did not adequately put them into practice. The principals had good record and financial management techniques although the experienced problems related to excessive fee balances form students. There was a fairly good and cordial school-community relationship, although they lacked teamwork with the principals hardly delegating administrative responsibilities to their deputies and heads of departments. It is recommended that principals should embrace team-work and delegate some responsibilities to their assistants, as well as instituting regular inspection of curriculum and instruction. [231 words]