This study explored the factors that influenced the understanding of good mathematics teaching. A mixed methodology was used investigate the beliefs of beginning secondary teachers on good mathematics teaching. The two research instruments used in this study were the survey questionnaire and an interview. Beginning teachers selected Immediate Classroom Situation, Mathematical Beliefs, Pedagogical Content Knowledge, and Colleagues as the top four factors from the survey analysis that influenced their understanding of good mathematics teaching. The study's results have implications on investigating specific mathematical content knowledge that is important for classroom instruction at the secondary level. Furthermore, this study can be used as a reference for teacher education programs to improve the effectiveness of the pedagogical courses in mathematics education.