Social impact assessment as a concept and practice is generally framed as a process for delivering socially equitable outcomes, and in particular, a vehicle for improving the lives of society’s most vulnerable and marginalised people. For example, the International Association for Impact Assessment 2015 guidance document makes the normative statement that projects should benefit local communities and be a ‘force for positive social change and beneficial social development’. Yet most guidance provides little prescription for what this looks like in practice. More recently, the New South Wales 2021 guideline includes distributive equity as a principle for social impact assessment, but its application is yet to be tested. This article discusses key dimensions of equity concepts, drawing on international social impact assessment guidance documents, academic literature on equity, fairness and justice, and case studies in Australia. We elaborate process/procedural/participative and outcome/distributive dimensions of equity. We further argue that, to reflect the International Association for Impact Assessment position, social impact assessment needs to defend its normative purpose of advancing equity, rather than simply ‘considering’ equity impacts.