This study attempts to identify the pre-service secondary mathematics teachers' epistemological beliefs towards learning, their educational beliefs, and critical thinking dispositions as well as the relationship between them. A relational survey model was employed and the study group consisted of 152 pre-service teachers. The study used Epistemological Beliefs Scale towards Learning (EBStL), The Educational Philosophy Tendencies Scale (EPTS), and Marmara Critical Thinking Dispositions Scale (MCTDS) as data collection tools. The results suggested that pre-service secondary mathematics teachers' epistemological beliefs and critical thinking dispositions were above the average value. Moreover, they were found to have progressive and reconstructivist tendencies. The results also revealed that the pre-service secondary mathematics teachers' epistemological beliefs towards learning did not differ across their gender, academic achievement, parents' educational level while significantly differed in terms of their grade level. The pre-service secondary mathematics' teachers' educational beliefs significantly varied across their gender, grade level while that was not the case for their academic achievement and parents' educational level. Besides, the results confirmed positive and significant relationships between the pre-service teachers' epistemological beliefs towards learning and their critical thinking disposition levels and progressivism, further positive and significant relationships were noted between the critical thinking dispositions and progressivism, reconstructionism and perennialism. Progressivism was found to be explained by epistemological beliefs towards learning and critical thinking dispositions; reconstructionism was found to be explained by critical thinking disposition; epistemological beliefs towards learning was determined to be explained by progressivism and critical thinking disposition, and critical thinking dispositions were identified to be explained by reconstructionism and perennialism.