Citizen initiatives (CIs), through their activities, have become a mechanism to promote empowerment, social inclusion, change of habits, and the transformation of neighbourhoods, influencing their sustainability, but how can this impact be measured? Currently, there are no tools that directly assess this impact, so our research seeks to describe and evaluate the contributions of CIs in a holistic and comprehensive way, respecting the versatility of their activities. This research proposes an evaluation system of 33 indicators distributed in 3 blocks: social cohesion, urban metabolism, and transformation potential, which can be applied through a questionnaire. This research applied different methods such as desk study, literature review, and case study analysis. The evaluation of case studies showed that the developed evaluation system well reflects the individual contribution of CIs to sensitive and important aspects of neighbourhoods, with a lesser or greater impact according to the activities they carry out and the holistic conception they have of sustainability. Further implementation and validation of the system in different contexts is needed, but it is a novel and interesting proposal that will favour decision making for the promotion of one or another type of initiative according to its benefits and the reality and needs of the neighbourhood.