Most Australian students receive sex education during school, but various literature suggests that they feel that their school-based sex education is neither relevant nor meeting their needs. This is particularly so for Year 11 and 12 students who have reported less experience of sex education in senior curriculum time in comparison to earlier year levels. With the National Curriculum covering up until the end of Year 10, states and territories are responsible for curriculum in senior secondary year levels, including sex education. However, these state interpretations vary widely and lack consistency in content and delivery. This research explores the nature, extent and quality of Years 11 and 12 school-based sex education from the perspective of recent graduates. It identifies who, what, and how graduates recall being taught, what they report was missing, and what they think should be included in Years 11 and 12 sex education. 60.84% of participants indicated not receiving any sex education in Years 11 and 12 and 79.72% view their sex education as lacking in quality. Inconsistencies in delivery and content amongst and between demographics such as gender, schooling sector, and region, demonstrate the need for a nationwide, mandatory, and comprehensive sex education curriculum for the senior years. This study encompasses a range of sexes, genders, sexualities, states/territories, and schooling sectors that add to the richness of the data. Most participants identify as cisgender females and, therefore, future research that specifically target cisgender male and other diverse populations is recommended.