[en] Prior research shows that trademarks positively relate to startups' growth and survival. However, empirical evidence on the impact of intellectual property rights (IPRs), especially trademarks, on the development of social startups' hybrid outcomes is limited. Our study aims to fill this gap by investigating how early trademarking relates to the sustainability and economic outcomes of social startups. Based on a sample of 485 social startups from Germany, we find that social startups that register a trademark within the first three years of their existence have both significantly higher sustainability and economic outcomes. Additionally, we identify that the geographical scope of a trademark relates differently to social startups' outcomes. Our results contribute to the emerging literature on startups’ role to achieve sustainability outcomes and to IPR research that lacks an understanding of the importance of trademarks for sustainable entrepreneurship. We provide several practical implications for social startups, impact investors, and policy-makers.