A sample of 987 height school freshmen (488 girls and 499 boys) was selected from the four educational districts in Shiraz using the cluster sampling method. The instruments were "Math Anxiety Scale" and "Attitude towards Math Scale". Factor analyzing the data yielded that the math anxiety is constituted of four factors: Math and figure anxiety, math test anxiety, negative feelings toward math, and concerns about math. The attitude toward math also consisted of two factors of math, enjoyment and math valuing. School achievement was measured using the final grades in math class. A regression analysis showed that the strongest predictor for math achievement in the math enjoyment factor. In other words, students liking math and enjoying involvement in situations requiring usage of math achieve more in this subject findings also show that any increase in negative feelings toward math, and in math and number anxiety is accompanied with a decrease in math achievement. The implication for the educational practitioners is obvious: motivational factors, especially attitude toward math must be focused on, teaching methods should be directed toward making the subject interesting and reducing any negative feelings and anxiety.