This study was conducted to compare the effectiveness of cooperative learning on mathematics anxiety, attitudes towards mathematics, and mathematics performance of the 12th-class Private school students of Herat City by using a quasi-experimental study. The statistical population included 650 individuals who were all high school students. 40 individuals were selected in two 20-individual groups by the multistage cluster random sampling method. The Math Anxiety Scale (Baloglu & Zelhart, 2007), the Mathematics Attitude Scale (Fennema-Sherman, 2000), and teacher-made tests of mathematics academic performance were used to collect data. The Jigsaw cooperative learning model was used to monitor the effectiveness of the presence or absence of cooperative learning, and the data were analyzed using SPSS software and one-way covariance analysis (ANOVA). In this study, three hypotheses were formulated, and their results indicated that there is a significant difference between the Jigsaw cooperative and traditional learning models in terms of math anxiety, attitudes towards math, and mathematics performance of the 12th-class Private school students of Herat City. It is concluded that the Jigsaw cooperative learning model can be used as one of the effective methods in schools to reduce mathematics anxiety, foster a positive attitude towards mathematics, and enhance the 12th-class Private school students’ mathematics performance.