The aim of this study is to develop a valid and reliable measurement tool that can determine the instructional capacity, according to teacher opinions. In the academic year of 2016-2017, 1011 teachers working in the public high schools and vocational technical schools in Ankara participated in the study. The total number of items on the scale was 43. The scale is arranged in 5-point Likert type scale format, with options ranging from 5 (Extremely) to 1 (Not at all). As a result of the analysis made, it consists of 6 factors. Sub-dimensions of the prepared scale are instructional management practices, teacher quality, curriculum-material quality and quantity, instructional climate, availability of learners to learn and financial resources. According to the findings, internal consistency reliability coefficients of scale factors were found high. Validity and reliability were provided by using descriptive factor analysis followed by confirmatory factor analysis. The developed scale can be used to measure instructional capacity.