Monitoring school functioning has recently drawn attention of policy makers, educationists, politicians, educational managers and all stakeholders of secondary education. The attention n has been influenced by direct relationship between monitoring and school improvements. Thus, the study sought to assess the contribution of administrative decentralization to effective monitoring of Tanzanian public secondary schools. This was accomplished by describing how monitoring has changed since June, 2014 when management of secondary education was devolved, examining mechanisms of control to address mismanagement of inputs, gauging capacity of local educational managers in supporting schools, assessing the extent to which inspectors liaise with schools and assessing the degree to which monitoring improves accountability in schools. Data was collected by questionnaire and from records of financial reports, legal document of 1978 and its 1995 amendments school planning documents and policy of 1995 document. The findings attested that there is change in school monitoring because inspection has adopted school strength approach and most of stakeholders involved in monitoring have relatively greater autonomy. However, despite impressive control mechanisms, leakage of school prevails and transfers of fund are characterized with delay, unpredictability flow and usually below the target. Schools to a large extent cover their operating expenses using parents and community contributions. Performance evaluations have very little impact on training and reward. Inspection findings and recommendations is very little accessible to parents, media and SMB. Furthermore, Accountability mechanisms to some extent are effective in monitoring the use of public offices and resources in the schools. To ensure, timely delivery of school inputs, direct school support mechanism should be used so that funds could directly be deposited into schools accounts. Government increase funds for schools because currently it spends less than the schools require. Remuneration and compensation for teachers should be reviewed. Inspection findings should be communicated to the stakeholder through the media. On recommendation for further study, the researcher suggest in depth case study to be done on monitoring school performance to explore reasons of delay, shortage and unpredictability flow of grants.