This chapter investigates how English philosopher, feminist, and political theorist Mary Astell offered a thoroughgoing and sustained critique of social contract theory in Some Reflections Upon Marriage (1700) and A Serious Proposal to the Ladies (1694). Like many other philosophers and political theorists marginalized on the basis of their identities, Astell was keenly attuned to the views, institutions, and systems of power that were used to perpetuate oppression. The chapter then looks at Astell’s criticisms of central features of social contract theory, particularly in the context of the socio-political institution of marriage as an analogue for the social contract. It assesses whether the analogue holds or whether it was simply a rhetorical device and what this means for how Astell understands marriage. Finally, the chapter suggests that Astell’s critique of social contract theory, especially its application to marriage, was an attempt to reshape the socio-political terrain of her time.