The purposes of this research were to study the administrative factors affecting to school curriculum development. The sample of 192 administrators and teachers were obtained by purposive random sampling. The instruments was a 5- scaled questionnaire and the statistics used in analysis data were percentage, mean , standard deviation, and multiple regression analysis. The results of the research revealed that overall; the level of administrative factors was at a moderate level. When considered separately, the aspects of administrative and practices policies and environment were at a high level. However, The aspects of personnel and facilities were at the moderate level. In terms of overall school curriculum development, it was at a moderate level. When considered aspects separately : Local needs determination; learning standard and expected outcome determination; a development of course description, content, and activity; and a development of instructional plan. Teacher?s manuals and Instructional media were at a high level respectively. The aspect of curriculum improvement and development and the aspect of basic information and analysis were at the moderate level. Furthermore, administrative factors affecting to the development of local curriculum and practices policies of personnel showed the algebraic equation forecasts : ZYtot = .261Z X 1 + .501Z X 4