This study aimed to determine the relationship between attitude, metacognitive awareness, and mathematics reasoning, as well as investigate the role of metacognitive awareness as a mediator. This study examined data from 378 pre-service teachers in Malaysia. The data were gathered by administering questionnaires and a mathematics reasoning assessment. The data were examined using the structural equation modelling technique. The results demonstrated substantial correlation through all variables, and path analysis revealed that metacognitive awareness mediates the relationship between attitude and mathematics reasoning. The results indicate that attitude has an essential impact on influencing the reasoning capabilities of preservice teachers in mathematics by fostering the growth of metacognitive awareness.