The purpose of this chapter is to review how well walking interventions have increased and sustained walking, and to provide suggestions for improving future walking interventions. A scoping review was conducted of walking interventions for adults that emphasised walking as a primary intervention strategy and/or included a walking outcome measure. Interventions conducted at the individual, community, and policy levels between 1990 and 2015 were included, with greater emphasis on recent interventions. Walking tends to increase early in interventions and then gradually declines. Results suggest that increased walking, and environmental-change activities to support walking are more likely to be sustained when they are immediately followed by greater economic benefits/time-savings, social approval, and/or physical/emotional well-being. Adaptive interventions that adjust intervention procedures to match dynamically changing environmental circumstances also hold promise for sustaining increased walking. Interventions that incorporate automated technology, durable built environment changes, and civic engagement, may increase cost-efficiency. Variations in outcome measures, study duration, seasons, participant characteristics, and possible measurement reactivity preclude causal inferences about the differential effectiveness of specific intervention procedures for increasing and sustaining walking. This review synthesises the effects of diverse walking interventions on increasing and sustaining walking over a 25-year period. Suggestions are provided to guide future development of more effective, sustainable walking interventions at the population level.