This study investigated the relationship between mathematics anxiety and mathematics teacher efficacy among 156 elementary pre-service teachers from a university in the southeastern United States. Data sources included the Mathematics Anxiety Rating Scale (MARS), Mathematics Teaching Efficacy Beliefs Instrument, and pre-service teacher interviews. Findings revealed a significant, negative relationship between mathematics anxiety and mathematics teachers' efficacy (r = -0.475, p less than 0.05). Specifically, the pre-service teachers with the lowest degree of mathematics anxiety had the highest levels of mathematics teacher efficacy. Interviews with pre-service teachers indicated that their mathematics anxiety is associated with efficaciousness toward mathematics teaching practices and is the basis for their mathematics teaching efficacy beliefs. (Contains 2 tables.)