Nowadays, cities and citizens are under pressure to cope with a wide range of challenges like climate change, shifting social dynamics and dependence on critical infrastructure. Increasing cities' resilience level is considered a priority; however, efforts so far have been made in a fragmented way, which prevents available resources being used in the most effective manner. The contribution of all city stakeholders, including public entities, private companies and citizens, to the resilience building process increases the effectiveness of the process. Therefore, developing effective mechanisms for fostering collaboration among city stakeholders such as public private people partnership (4Ps) is a promising way for addressing this need. This paper presents a Delphi study that validated the final version of a 4P development framework. This framework is composed of 16 successful characteristics classified within three dimensions that need to be implemented to develop 4Ps, the three development stages that 4Ps should go through and an implementation methodology that defines the order for implementing the characteristics based on the three development stages. One of the main conclusions obtained is that first, the characteristics classified in the stakeholder relationship and information flow dimensions should be implemented and afterwards, the characteristics of the conflict resolution dimension.