This study developed the Japanese version of the Multidimensional School Anger Inventory (MSAI; Smith & Furlong, 1998). The MSAI was devised to assess anger in the school context from a multidimensional perspective, which includes Anger Experience (affective component), Cynical Attitude (cognitive component), Destructive Expression and Positive Coping (behavioral component). The responses of 3 443 students from elementary to high school, age 10 to 17 on the Japanese version of the MSAI were used in the analyses. Exploratory and confirmatory factor analysis identified that the four-factor structure of the J-MSAI was the same as for the original MSAI. The reliability of the scale was supported by internal consistency and test-retest stability for the subscales. The construct validity of the scale was supported by cross-instrument correlations. Furthermore, the results showed that junior high and high school students had higher scores for Cynical Attitude than elementary school students, whereas developmental level had little effect on Anger Experience and Destructive Expression.