Food waste is a global problem, with estimates of a third of all food produced going to waste(1). In 2015, the United Nations set Sustainable Development Goal (SDG) Target 12.3, to halve food waste by 2030(2). To reach this goal, following the Target-Measure-Act approach is considered best practice(3). At the University of Otago, in Dunedin, Aotearoa New Zealand, approximately 3,500 students live across 14 fully catered residential colleges. The University of Otago has formally committed to pursuing the SDGs, and therefore reducing food waste. To track progress towards SDG 12.3, baseline measurements of food waste at the residential colleges are required. This research aimed to quantify food waste from the residential colleges, as well as to qualitatively discuss reasons for the waste and potential ideas to reduce waste. On three days at each of the 14 residential colleges, preparation, servery, and plate waste were measured from breakfast, lunch, and dinner, following a protocol developed from the Waste and Resources Action Programme Food Loss and Waste Standard. Additionally, five focus groups were conducted across three residential colleges, with students and staff, to discuss food waste at the residential colleges. An average of 172 g (95% CI 154 g to 191 g) of food waste were produced per student per day, with approximately 50% being plate waste, 35% being servery waste, and 15% being preparation waste. Reinforcing the quantitative data, in the focus groups staff voiced that the plate waste was a concern to them. Ways to reduce plate waste were discussed and included increasing awareness through making the waste more visible, as well as improving communication between kitchen staff and students particularly regarding serving sizes and preferred menu items. Servery waste was also considered, with more consistent forecasting of meal attendance across the residential colleges and a range of solutions for leftovers, such as a fridge for students or donation to other organisations, being suggested. With these baseline measurements of quantities of food waste produced at the University of Otago’s residential colleges, actions taken to reduce and mitigate food waste can be measured for effectiveness, and steps can be taken towards achieving SDG 12.3 collaboratively across the tertiary education sector.