This paper assesses the relevance of social investment in relation to the 2030 Agenda and its Sustainable Development Goals (SDGs), targets, and indicators. The research question is: How could social investment support the achievement of Sustainable Development Goals? The thesis conceptualises social investment, sustainable development, and sustainability, before turning to the issue of how social investment could enhance its impact by focusing on areas of policy that it has not considered typically. This thesis goes beyond addressing the SDGs themselves to consider other issues that shall arguably be significant in relation to achievement of the 2030 Agenda, such as the contentious matter of limits to growth. The thesis includes a content analysis of the global indicator framework for the 2030 Agenda, based upon social investment-related search terms and focused reading of particular examples from the social investment literature. The first part of the analysis suggests that social investment in its current form can contribute towards Goal 4 on quality education and Goal 8 on decent work and economic growth; and to a somewhat lesser extent towards Goal 1 on no poverty, Goal 5 on gender equality, and Goal 10 on reduced inequalities. The analysis considers subsequently further SDGs that social investment could ultimately support. While recognising the value of social investment as understood usually for policymaking to achieve the SDGs, the concluding section suggests that a broadened version of social investment could strengthen policy relevance.