This thesis joins the current debate about the paradox of constituent power in political theory. The paradox of constituent power is reflected by the tensional relationship between constituent power and constitutional form. It is usually addressed by privileging one of the two. This thesis constructs an Arendtian theory of constituent power for addressing the paradox, which accommodates the two contrasting elements of constituent power. I first argue that the two contemporary approaches to addressing the paradox compromise one of the two necessary dimensions of constituent power: the transgressive dimension and the stabilising dimension. This is accomplished by examining Bruce Ackerman's dualistic democratic theory and Antonio Negri's revolutionary democratic theory. I then argue that an Arendtian theory of constituent power is able to accommodate the two dimensions of constituent power. The transgressive dimension of constituent power is theorised by interpreting Hannah Arendt's concepts of 'the people', which is a worldly political society, and 'principle', which is the shared political value within a constitutional form. The stabilising dimension of constituent power is theorised by interpreting Arendt's concept of 'authority', which is the augmentation of the foundation of the constitutional form by exercising transgressive constituent power. Finally, I argue that the Arendtian theory of constituent power can be realised in political reality in the form of constituent civil disobedience. Civil disobedience can be both the formation of a new people and the exercise of constituent power that augments the foundation of a constitutional form at the same time.