Separation of generations, arising from factors including societal attitudes, geographical separation, and age segregation, can contribute negatively to opportunities for healthy ageing. Intergenerational programs, initiatives fostering intergenerational connection and contact, are one such way to mitigate these challenges. Numerous systematic reviews have examined the efficacy of intergenerational programs on health and wellbeing outcomes across population groups. However, no synthesis currently exists to collate conceptual theories and measurement methods used to examine health and wellbeing outcomes in intergenerational programs. This umbrella review searched eight electronic databases to identify systematic reviews of familial and non-familial intergenerational programs involving two or more generational groups. A narrative synthesis of findings was undertaken. Of 1787 articles retrieved, 1149 duplicates were removed, 638 articles were screened, and 34 retained for analysis. Population characteristics, types of intergenerational activities, conceptual paradigms/theory, and health and well-being outcome measurement tools identified will be reported on. A range of theoretical frameworks were identified, reported in 65% (n=22/34) of reviews. A total of 184 standardised health and wellbeing outcome measurement tools were identified, with 43 (identified in at least 2 systematic reviews) explored in-depth. Results found that authors at all levels of research need to align their research more explicitly with theory, and greater use of standardised health and wellbeing outcome measurement is needed to promote evidence-informed intergenerational program facilitation and evaluation. Further, consideration of research efforts in working towards a consistent set of holistic health and wellbeing outcome measurement methods is discussed, to promote clarity, consistency, and generalisability of research findings.