Massive open online courses (MOOCs) can be designed with different pedagogical approaches and course components as in face-to-face courses. In this context, the development of some standards and field-specific design principles related to MOOCs is seen as a critical step for the creation of quality online courses. The aim of this study is to examine the MOOC experiences of the learners in mathematics education and proposing reflections about design principles of MOOCs for mathematics education. In this respect, the MOOC experiences of 30 teacher candidates enrolled in MOOCs (with mathematic education context) were analyzed, and the general course structure, pedagogical orientations, and mathematical connection elements used in these MOOCs were examined. The data obtained from the participants revealed a comprehensive course evaluation structure including 7 categories and 85 codes under 3 themes and mathematical connection findings consisting of 3 categories and 3 subcategories. The research findings uncovered that teacher candidates had course experiences that differed according to national/international MOOC evaluation criteria in terms of audiovisual elements, video/course durations, interaction-feedback features, teaching methods, measurement/evaluation, and mathematical connection dimensions. Course evaluation codes/propositions and mathematical connection findings that emerge as a result of this research can be considered as a resource that can be used in the design of MOOCs to be planned in mathematics education.