Background: Measures of quality of life (QOL) must be appropriate for specific groups but comparable across groups. In this paper, we compared how QOL is measured in research with older adults with and without an intellectual disability (ID). Methods: Measures used in 2 population studies of older adults with and without ID (Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing [IDS-TILDA], and The Irish Longitudinal Study on Ageing [TILDA]) were examined. Framed by Schalock's Quality of Life Framework, conceptual content of measures of emotional wellbeing and self-determination were compared. The acceptability and concurrent validity of IDS-TILDA measures were evaluated. Results: The same measures of emotional wellbeing were identified in both surveys. However, measures of self-determination captured different aspects of the construct. Concurrent validity between self-determination and emotional wellbeing measures in IDS-TILDA was weak. Conclusions: Research with adults with and without ID is limited by the nature of current inclusive QOL measures: Instruments are required that have adequate conceptual coverage and are comparable across groups but appropriate and feasible to use.