The study aimed to reveal the effectiveness of a training program to develop the competencies of measurement and evaluation of the English language teachers in cycle one schools. The quasi-experimental approach was used. The sample of this study consisted of twenty English teachers for experimental group selected from four schools and the control sample consisted of twenty teachers from three schools from Aldakhilia governorate for the academic year 2018/2019. In order to achieve the objectives of the study, the researcher prepared a training program in the competencies of measurement and evaluation, based on the standards of measurement and evaluation competencies issued by the American Union of the National Council of Teachers for the measurement and evaluation of the National Education Association. In addition, this study used a cognitive test (Assessment Literacy Inventory) and a short questionnaire. The results of the study showed that there were significant differences in the means of measurement and evaluation competencies between the experimental group and the control group in the post-test favoring the experimental group over controlling group. The results also indicated significant differences between pre-test and the post-test of the teachers' performance in the experimental group in favor of post-test.