Teacher education has an effect on the quality of instruction and consequently on students’ learning, and achievement. Research in this area supports the presumption that the willingness to attend, for example, in-service training, is related to formal qualifications and work experience, but may also be affected by the current context. The focus of this paper is to understand these relationships in the South African context, where the enhancement of teacher qualifications has been identified as a core area of action; the policy on teacher education was renewed in 2007 and subsequently in 2014. The analysis is based on Trends in International Mathematics and Science Study data from 2003, 2011, and 2015. Multilevel regression models were calculated using SAS/STAT. Results show that South Africa has made substantial progress in uplifting teacher’s formal qualification levels and in reducing structural inequality within its education system. Out-of-field teaching is still shown to be a common phenomenon and unevenly distributed. However, teachers with different qualification profiles do not differ in their usage of professional development opportunities. Also the teacher’s formal level of education is in general not significantly associated with students’ mathematics achievement. If at all, differential advantages are found for formal qualification rather than for specialization.