Abstract There is consensus in the international mathematics teacher education literature that teachers should, at the most basic level, have mastery of the content knowledge they are required to teach. In this paper we test this assumption empirically by analyzing the South African SACMEQ 2007 mathematics teacher test data which tested 401 grade 6 mathematics teachers from a nationally representative sample of primary schools. With items matched to curriculum grade bands, findings indicate that 79% of grade 6 mathematics teachers showed content knowledge levels below the grade 6/7 band, and that the few teachers with higher-level content knowledge are highly inequitably distributed.