RRIstart responds to the EU efforts to foster impact investment (investment that delivers social, environmental and economic benefits) by developing an innovative RRI-based model for startups, complemented by an RRI-based impact investment indicator list in a multi-stakeholder (beyond quadruple helix) context. Through RRIstart, the consortium aims to demonstrate the value of RRI for the STEM entrepreneurship ecosystem. At the moment, startups and investors do not adopt existing RRI principles and indicators due to the limited compatibility of existing RRI models (tailored mostly for large organizations). Nevertheless, by adopting a lean/agile approach to RRI embedment, RRIstart proposes a novel RRI model for startups blended with novel RRI-based impact investment indicators. RRIstart tests the developed innovation through a translational piloting approach (from lab to market). Three pilots will be organized (on environmentally sustainable startups from Northern Europe, 3D printing & advanced materials in Italy and bioeconomy (agrifood) in Greece). In each pilot, extended quadruple helix actors will be involved in order to assess the feasibility of embedding RRI in startups and to facilitate (public and private) impact investment through the RRI-based indicator set. By adopting a multi-disciplinary approach in a multi-sectoral STEM context, RRIstart will update the SwafS knowledge base through the following: contributing to 9 MoRRI indicators and 9 SDGs; boosting societal engagement towards STEM startups; fostering the recruitment of talent for STEM startups; pairing scientific excellence with social awareness and responsibility by facilitating RRI-based startups and impact investment; creating new market opportunities; bring society closer to science and innovation through impact investment (show-casing the clear benefits of societal engagement in innovation development); and overall, making EU startups and investors more RRI-aware.