Most people would agree that helping students learn new information is important; however, there are numerous methods for achieving this goal, and not all of them have been proven to be effective. One method with intuitive appeal and some empirical backing is prompting students to self-explain. A self-explanation can be defined as generating explanations to oneself in an attempt to make sense of new information (Chi, 2000). The self-explanation effect has been studied since the 1980s, and has been examined in many learning domains, from chemistry to mathematics to argumentation (e.g., Chi, Bassok, Lewis, Reimann, & Glaser, 1989). The purpose of the current meta-analysis reported in this paper is to determine if there is a significant, positive self-explanation effect in mathematics domains or not. In addition, this meta-analysis will examine the possibility that study setting might relate to the effectiveness of self-explanation in mathematics. This meta-analysis illustrates that there is some evidence for the benefits of self-explanation in math; however, the evidence is not as strong as some researchers might think. It seems that self-explanation is not harmful to students, but whether or not it is worth the time it takes to go through them is unclear. Future studies may want to include a control group that does not self-explain so that a direct comparison can be made to test for the self-explanation effect. (Contains 1 table and 1 figure.)