Background: The study explored experiences of health and social care practitioners within a community learning disability team in undertaking mental capacity assessments with people with learning disabilities. Materials and Methods: Eight practitioners were interviewed using a semi-structured interview schedule. Results: The information gained was analysed using thematic network analysis. Twelve basic themes emerged which fit into five organising themes labelled: "systemic barriers to assessment"; "capacity assessing as a process"; "person-specific challenges"; "protective practices"; and "protection of a fundamental human right". A global theme, "freedom of action versus restrictions on action", was identified. Conclusions: The themes highlighted that there were a range of organisational, systemic and person-specific factors that impacted on the perceived quality of and assessors' confidence in their assessments of mental capacity. Furthermore, these factors appeared to create a range of tensions for assessors increasing the likelihood of cognitive dissonance. Practice implications surround maintaining knowledge, ensuring adequate skills in the practical application of knowledge and reducing organisational barriers.