Given the ambiguity surrounding the extent and experience of neurocognitive disability (NCD) among marginalised Aboriginal and/or Torres Strait Islander peoples in Australia, evidence regarding the level and nature of NCD is crucial to ensure equitable access and inclusion into the National Disability Insurance Scheme (NDIS). This paper reports the results of the implementation of The Guddi Protocol (a culturally informed and appropriate screening protocol for Aboriginal and/or Torres Strait Islander peoples) at two locations in Queensland. Results indicated high levels of NCD, and additional qualitative data revealed a number of factors associated with the complex disablement of study participants, namely: i) intergenerational trauma; ii) a social context of disadvantage, marginalisation and exclusion; and iii) the non-identification of disability. The results are linked to implications for NDIS inclusion for this population, and recommendations are made. Unless the extent and nature of complex disability and the issues surrounding culturally safe policy, and service design and engagement are addressed with and by Aboriginal and Torres Strait Islander peoples, including those who experience complex disablement, marginalised people will continue to be effectively excluded from the NDIS.