Policy decisions are based on evidence that demonstrates the effectiveness of interventions; however, the quantity and type of evidence that is needed to demonstrate the effectiveness of an intervention is not universally agreed upon. The aim of this study was to collaborate with researchers who have not been involved directly in Family Wellbeing interventions to lead a review of characteristics of the Family Wellbeing intervention evaluation output to date, and to assess for evidence of the FWB intervention’s impact on participants and their communities. The study found that where it is not appropriate or viable to conduct research, such as randomised control trials, alternative ways of providing evidence to demonstrate the effectiveness of an intervention is vital. This review suggests that Family Wellbeing interventions are having a positive impact and promoting change in the lives of participants, their families and their communities. Hence, for complex interventions, such as those with Indigenous populations, evidence should demonstrate effectiveness against prescribed outcomes, as well as critical aspects behind how and why a complex intervention was successful.