Social policy is most effective when evidence-based. In this research, we scrutinise 11 surveys to produce evidence on the subjective well-being (SWB) of older migrants in the Netherlands. The descriptive analysis and literature review revealed that the study of the diversity among older migrants is hindered by several factors, including the inclusion of a limited number of distinct migrant groups, their almost exclusive comparison to non-migrants, and a focus on first-generation and urban-based migrants. Different concepts are used for three dimensions of SWB, both migrant-specific and general. The validity of concepts and measurement instruments is not well examined. By means of multi-group analysis, we demonstrate that the overarching concept of SWB is multidimensional and cannot be easily used to compare different groups of migrants. In conclusion, we argue that survey data can be used to further refine the concept of SWB, compare differences between and within migrant groups and over time, and ultimately inform social policy better.