This article discusses the mathematical needs of secondary teachers, in particular senior secondary teachers who are preparing students for tertiary mathematical study. It also reports on data concerning secondary mathematics teacher qualifications in New Zealand, Australia and the United Kingdom. Despite an increasing need for both deeper and wider mathematical understanding, the levels of mathematical qualifications of secondary teachers in all three countries appear to have declined since the 1970s, with the current proportion of teachers without post-secondary mathematics qualifications being between 20 and 30%. The implications for mathematics learning are discussed and it is recommended that all second year mathematics teachers should have the equivalent of second year university mathematics. (Contains 1 note.)