In contemporary Australia, an informed citizenry and a workforce with strong STEM-related skills are increasingly taken for granted. Yet it has also been well-established that females are underrepresented in STEM-related fields. In this article, Helen Forgasz and Gilah Leder focus on the M in STEM, that is, mathematics, and with a particular emphasis on gender. They begin by examining how gender has played a part in mathematics participation and learning over time. They then explore the more recent status of participation and achievement in mathematics by gender, and examine people's attitudes and beliefs about gender and mathematics. They conclude with a series of suggestions on how schools and teachers can identify if there are gender issues in mathematics in their own contexts and, if found, how they might go about achieving gender equity.