Results of 151 studies were integrated by meta-analysis to scrutinize the construct mathematics anxiety. Mathematics anxiety is related to poor performance on mathematics achievement tests. It relates inversely to positive attitudes toward mathematics and is bound directly to avoidance of the subject. Variables that exhibit differential mathematics anxiety levels include ability, school grade level, and undergraduate fields of study, with preservice arithmetic teachers especially prone to mathematics anxiety. Females display higher levels than males. However, mathematics anxiety appears more strongly linked with poor performance and avoidance of mathematics in precollege males than females. A variety of treatments are effective in reducing mathematics anxiety. Improved mathematics performance consistently accompanies valid treatment.