There are many areas of convergence and mutual growth between health impact assessment (HIA) and health promotion. However, HIA is often considered a practical implementation tool and therefore not particularly suited for research. In fact, HIA is more than a tool, it is a health promotion approach and a means to effectively implement Health in All Policies (HiAP). The aim of this chapter is to investigate whether HIA can contribute to meeting research challenges in the field of health promotion. Conversely, the question is also asked whether health promotion research may be a useful source of data and insights for HIA practitioners. Across a series of examples drawn from the work of a group of HIA researchers over 25 years of practical experience, the case is made for a strong and growing link between HIA and health promotion research. The implications of this practical and scientific convergence are discussed.