Teaching efficacy, teaching anxiety, and teaching knowledge are crucial factors in effective teaching. This study investigated the mediating role of mathematics teaching efficacy (MTE) in the relationship between pedagogical content knowledge (PCK) and mathematics teaching anxiety (MTA) for pre-service mathematics teachers. The participants were 463 volunteer pre-service teachers who completed a questionnaire package that included the MTE Scale, the MTA Scale, and the PCK Scale. The theoretical model was tested using structural equation modeling and a bootstrapping procedure. It was revealed that MTE has a partial mediating role in the relationship between PCK and MTA for pre-service teachers. The findings indicated that a high level of PCK increases pre-service teachers' MTE, which decreases their MTA. Although PCK predicts MTE that in turn predicts MTA, more longitudinal and experimental studies are needed to better understand this sequence.