When geometry teaching lacks elements of flexibility, inclusivity and accessibility, it is often difficult for learners to follow and understand what they are being taught. In line with this, this paper reports on the application of universal design for instruction (UDI) to guide flexible and accessible teaching of geometry to maximise learning. UDI is an approach to teaching that uses a variety of flexible, inclusive and accessible teaching methods to remove barriers to learning, in order to give all learners equal opportunity to succeed. Eight grade 9 mathematics teachers in one of the largest secondary schools in the Motheo district in South Africa were purposively selected to participate in this qualitative case study that was underpinned by sensemaking theory as a lens. These teachers have previously undergone training on the application of UDI in teaching mathematics. Focus group discussions and lesson observations were used to generate data, whilst content analysis was used to analyse the generated data. The findings of the study revealed the positive effects of UDI in terms of guiding flexible, inclusive and accessible teaching of geometry to maximise learning. Thus, this study suggests implications for teaching geometry using UDI to maximise learning.