This chapter aims to contribute to linking policies and actions towards better integration of mental health systems and humanitarian efforts within mental health and psychosocial support. Despite widespread agreement on the importance of bridging the gap between the two, the link remains a challenge in practice. We discuss the crucial link between long-term systems for health and care and immediate mental health and psychosocial humanitarian action in terms of similarities and difficulties regarding policies and action, and how the potential for such complementarity can be used. In this chapter, we discuss some of the differences between the two approaches and suggest ways to promote the integration through MHPSS policies and action, building on overlapping or complementary aspects, such as do no harm. Community- based services, involvement of stakeholders, multisectoral action, and capacity development, including a stronger workforce, can be used to invest in the mental health systems before, during, and beyond emergencies.