This systematic review examines the sustainability of new programs and innovations in healthcare, focusing on the empirical literature and recommendations for future research. The review identifies 125 studies that met the inclusion criteria, covering a range of fields including medical, public health, mental health, and educational interventions. The studies were analyzed to determine the factors influencing the sustainability of these programs and interventions, as well as the methods used to assess sustainability. The review found that sustainability is a complex and dynamic phenomenon influenced by various factors, including organizational context, capacity, processes, and the characteristics of the innovation itself. While many studies relied on self-reports or retrospective designs, few employed rigorous methods to evaluate sustainability. The majority of studies focused on the continuation of program elements rather than the full implementation of the program. The results indicate that partial sustainability is more common than full continuation, and that the impact of partial sustainability on recipient-level outcomes is not well understood. The review also highlights the importance of fidelity and adaptation in the sustainability of interventions. While fidelity is crucial for some interventions, flexibility and adaptive capacity are important for others. The findings suggest that the sustainability of interventions is influenced by a combination of factors, including the characteristics of the innovation, the context in which it is implemented, and the capacity of the organization to sustain the intervention. The review concludes that future research should focus on developing clearer definitions of sustainability, using more rigorous methods to assess sustainability, and considering the interactions between various factors that influence sustainability. It also emphasizes the importance of studying the processes and interactions that contribute to the sustainability of interventions, as well as the role of fidelity and adaptation in achieving long-term success. The review recommends that future studies consider the dynamic nature of sustainability and the need for ongoing evaluation and modification of interventions to ensure their long-term effectiveness.This systematic review examines the sustainability of new programs and innovations in healthcare, focusing on the empirical literature and recommendations for future research. The review identifies 125 studies that met the inclusion criteria, covering a range of fields including medical, public health, mental health, and educational interventions. The studies were analyzed to determine the factors influencing the sustainability of these programs and interventions, as well as the methods used to assess sustainability. The review found that sustainability is a complex and dynamic phenomenon influenced by various factors, including organizational context, capacity, processes, and the characteristics of the innovation itself. While many studies relied on self-reports or retrospective designs, few employed rigorous methods to evaluate sustainability. The majority of studies focused on the continuation of program elements rather than the full implementation of the program. The results indicate that partial sustainability is more common than full continuation, and that the impact of partial sustainability on recipient-level outcomes is not well understood. The review also highlights the importance of fidelity and adaptation in the sustainability of interventions. While fidelity is crucial for some interventions, flexibility and adaptive capacity are important for others. The findings suggest that the sustainability of interventions is influenced by a combination of factors, including the characteristics of the innovation, the context in which it is implemented, and the capacity of the organization to sustain the intervention. The review concludes that future research should focus on developing clearer definitions of sustainability, using more rigorous methods to assess sustainability, and considering the interactions between various factors that influence sustainability. It also emphasizes the importance of studying the processes and interactions that contribute to the sustainability of interventions, as well as the role of fidelity and adaptation in achieving long-term success. The review recommends that future studies consider the dynamic nature of sustainability and the need for ongoing evaluation and modification of interventions to ensure their long-term effectiveness.