This study examined the structure of middle school students' general epistemological beliefs and domain-specific mathematical problem-solving beliefs by asking whether the 2 belief systems are related and whether they predict students' academic performance. Over 1,200 seventh- and eighth-grade students completed an Epistemological Questionnaire, the Indiana Mathematical Belief Scale, and the Fennema-Sherman Usefulness Scale. Based on regression analyses, beliefs in quick/fixed learning (i.e., that learning is fast and instinctual) and studying aimlessly (i.e., studying without strategy) were significantly related to beliefs about effortful math, useful math, understand math concepts, and math confidence. Furthermore, path analysis suggested that both general and domain-specific epistemological beliefs predicted academic performance as measured by solving mathematic problems and overall grade point average.