Background: Social and physical environments are important drivers of socioeconomic inequalities in health behaviour. Although many interventions aiming to improve such environments are being implemented in underprivileged neighbourhoods, implementation processes are rarely studied. Acquiring insight into successful implementation may improve future interventions. The present study aimed to investigate factors influencing the reach, effectiveness, adoption, implementation and maintenance (RE-AIM) of social and physical environmental interventions aimed at promoting healthy behaviour in underprivileged neighbourhoods in The Netherlands. Methods: A large set of theory-based factors of successful implementation was assessed for 18 implemented interventions in three underprivileged neighbourhoods. Expert and target group panels scored the RE-AIM dimensions for each intervention. We analyzed the statistical significance of associations between theory-based factors and the actual RE-AIM in a statistical model, to identify factors associated with increased RE-AIM. Results: Six factors were identified: effectiveness and implementation success were higher when the target group was involved in the planning process, whereas maintenance increased in the absence of competition with other projects. If the current situation was inventoried during intervention development, the effectiveness, adoption and implementation were higher. These dimensions were also higher when the target group was informed before implementation. Involvement of the target group during implementation resulted in higher reach, effectiveness and adoption. Finally, lack of intervention staff worsened the reach. Discussion: This study contributes to the evidence base for effective implementation of environmental measures aimed at promoting healthy behaviours. In particular, interventions in which the target group was involved in the implementation process were associated with higher RE-AIM outcomes.