John Locke is commonly associated with the emergence of classical liberalism and the most fundamental features of modern politics, especially with respect to consent based government, constitutionalism, individual rights, and toleration. There is a great body of Catholic political thought, however, developed just prior to Locke's life and career, that also provided theoretical treatments of many of the same concerns that animated early modern liberalism. Famous among his contemporaries as a theologian and philosopher, Francisco Suárez, S.J., died only a decade and a half before Locke was born and wrote on many of the same political issues that made Locke famous. Although Suárez is less well-known now, he had an immediate connection to Locke: Robert Filmer, the man against whom Locke directed the entire First Treatise on Government, was himself writing against Jesuit political thought and mentions Suárez by name as an example.Suárez and Locke's mutual antagonism to divine right absolutism is not the only thing they had in common. Both are credited as early theorists of the social contract and both use their theories of consent based government to develop theories of resistance and change for government. The similarities in their political thought are made more remarkable by considering their opposing philosophical and theological stands: in addition to being a Catholic priest, Suárez was an Aristotelian operating fully within the scholastic tradition; Locke was attracted to the dissenting Protestants in England, and rejected scholastic methods of inquiry in favor of a more scientific, empirical approach. In this dissertation I will closely examine the thought of Suárez and Locke on human life, natural law, and political community in order to determine whether their outstanding theological and philosophical disagreements affect their political conclusions as well. I argue that despite their many political similarities, these more fundamental differences do lead to substantially different political thought, especially concerning the areas of religion and toleration, the direction of legislation, and moral obligation, and that Suárez's preservation of the theological and philosophical tradition allows him to avoid problems that Locke's newer approach faces.