Purpose: This paper reviews extant research related to the impact assessment of social innovation and identifies several barriers to this assessment. Following this is a proposal of interventions to overcome these barriers. Originality/value: Social innovation has played an essential role in enhancing positive changes for society. Nonetheless, measuring its impact is a very significant challenge due to the many barriers faced in selecting metrics that fit its definition and goal. Recognizing these challenges, the main contribution of this paper was to identify the most common barriers and to suggest how these barriers can be overcome. Design/methodology/approach: Two approaches were considered in this research. On the one hand, a bottom-up approach was applied to review relevant literature related to impact metrics for social innovation and good practices toward social innovation impact assessment. On the other hand, we used a top-down approach through collecting and analyzing research projects related to identifying metrics of social innovation impact, broadly disseminated and well-consolidated in the current literature. Findings: This research offers valuable insights to academic researchers, policy decision-makers, and practitioners working in the field of social innovation by identifying and classifying the main barriers faced to measuring the impact of social innovation, namely lack of stakeholder awareness in the field of social innovation, difficulties in selecting the metrics to assess social innovation, problems in selecting criteria to identify best-fitted indicators to social innovation, lack of beneficiaries engagement, lack of financial and public support, and lack of consensus in the social innovation definition.