Background: Mainstream economic evaluations methods may not be appropriate to capture the range of effects triggered by interventions for people with intellectual disabilities. In this systematic review, we aimed to identify, assess and synthesise the arguments in the literature on how the effects of interventions for people with intellectual disabilities could be measured in economic evaluations. Method: We searched for studies providing relevant arguments by running multi-database, backward, forward citation and grey literature searches. Following title/abstract and full-text screening, the arguments extracted from the included studies were summarised and qualitatively assessed in a narrative synthesis. Results: Our final analysis included three studies, with their arguments summarised in different methodological areas. Conclusions: Based on the evidence, we suggest the use of techniques more attuned to the population with intellectual disabilities, such sensitive preference-based instruments to collect health states data, and mapping algorithms to obtain utility values.