This study analysed secondary TIMSS 2019 data for respondents from South Africa and proposed a model containing ten constructs; nine independent variables (socio-economic status and eight variables about safety aspects in schools) and one independent variable (mathematics achievement). Qualitative data was also collected using interviews and field notes. The HLM model identified the following significant predictors to learners' mathematics achievement: learners whose family members were frequently insulted; who were victims of theft; who were forced to do things they didn't want to do; who were physically hurt; living in impoverished areas; enrolled in schools with a shortage of or inadequate instructional space; enrolled in schools where physical injury amongst learners is a problem; disrespecting property. Findings from the thematic analysis indicated that participants believed that schools' safety concerns are associated with learners' mathematics achievement and that difficulties in developing and implementing school safety policies are due to a lack of training.