This literature review provides school psychologists with an understanding of the important issues related to the gender gap in mathematics achievement. The extant literature suggests that girls tend to receive lower scores than boys on standardized math tests, but in general these differences tend to be small. However, girls have better classroom grades and outperform boys on curriculum-based measures. One of the key factors that account for these differences involves self-efficacy. The role of self-efficacy in mathematics achievement is discussed as well as relevant recommendations for school psychologists.