Issues of social justice in higher education together with a focus on access or widening participation have become of increasing importance globally. Given the complex theoretical terrain of social justice and the tensions inherent in applying social justice frameworks within higher education, and particularly in the area of access, this paper argues that it is necessary to take a step back and reflect on key theories of social justice and their implications for higher education. The paper considers three leading theorists of social justice whose work is commonly applied in higher education contexts and provides an account of the implications of this work for a specific social justice challenge, that of increasing access to university. The complexities of access and success in South African higher education are used as an illustrative case. On the basis of this conceptual analysis an argument is presented for the capabilities approach as a particularly productive theoretical approach in the context of university access for promoting more just outcomes, through a specific consideration of student agency and the interaction of this agency with institutional contexts.