The purpose of this study was to develop a scale to assess the frequency of using classroom assessment tools and methods for mathematics teachers. This study was conducted on 320 Turkish mathematics teachers. The data were analysed using the SPSS 17.0 and LISREL 8.8 statistical software packages. EFA and CFA, item-total correlations, and convergent and discriminant validities were used to assess the construct validity. EFA and item analysis were performed with 170 mathematics teachers. After EFA, a four-factor scale with 25 items was identified, explaining 52.38% of the variance. The CFA was carried out with 150 mathematics teachers. The first and second-order CFA results indicated that the scale model had good fit indices, and the convergent and discriminant validity of the scale was confirmed. The Cronbach's alpha and composite reliability (CR) coefficients were satisfactory. The results of this study showed that the scale is a reliable and valid instrument for assessing the frequency of mathematics teachers’ use of classroom assessment tools and methods.