The main purpose of this research was to study the desirable competencies of external evaluators in basic education based on the opinions of school administrators in basic education. Minor purposes were as follows 1) To study variables of desirable competencies of external evaluators in basic education. 2) To study factors of desirable competencies of external evaluators in basic education. 3) To compare opinions of school administrators in basic education based on under jurisdiction between school in the Office of the National Primary Education Commission (ONPEC) and Department of General Education (DGE), argument of school between had argument and without argument. Population in the school administrators under jurisdiction of the Commission for Basic Education who were external evaluate. The Samples consisted of 714 school administrators under jurisdiction of the Commission for Basic Education obtained by two-stage random sampling. Data was colllected by questionnaire and analyzed the descriptive statistics, exploratory factor analysis and manova using SPSS for Window version 12.0. Conclusions of the research were : 1. There were 84 variables of desirable competencies of external evaluators in basic education. 2. The 7 factors of desirable competencies of external evaluators in basic education were 1) knowledge and ablility to evaluate 2) communication and group working ability 3) ethics of external evaluators 4) display democrat 5) data feedback ability to school 6) knowledge of administer school and 7) computer ability. Percent of variance was 66.941 3. The opinions of school administrators in basic education based on under jurisdiction between Office of the National Primary Education Commission (ONPEC) and Department of General Education (DGE) finding the opinions of school administrators Department of General Education (DGE) according to mean factor score of the higher than that of the Office National Primary Education Commission (ONPEC) in knowledge and ability in evaluate, communication and group working ability (different in .01 significant level), argument of school between had argument and without argument finding the opinions of school administrators who had argument according to mean factor score of the higher than that of without argument in communication and group working ability (different in .05 significant level).