This paper addresses the question of how design can contribute to the happiness of individuals–to their subjective well-being. A framework for positive design is introduced that includes three main components of subjective well-being: pleasure, personal significance and virtue. Each component represents an ingredient of design for happiness, and we propose that design that expressly includes all three ingredients is design that promotes human flourishing. People who flourish are developing as individuals, live their lives to their fullest potential, and act in the best interests of society. The intention to support human flourishing is the explicit, central design objective of positive design. Five characteristics of positive design are proposed, all of which are of relevance to organizing design processes that intend to result in designs that stimulate human flourishing. In addition, some contemporary design approaches are discussed that focus on quality of life, including nudge, capability approach, and experience design. Four important research challenges are outlined to indicate directions for a research agenda. Together with the framework, these research directions are intended to offer inspiration for designers and design researchers to join forces in their endeavours to design for subjective well-being.