This paper examines the relations between identity, otherness and alterity in the field of ethics and, especially, in that of political philosophy. For this, I refer to the work of three eminent thinkers: the Mexican philosopher Luis Villoro, and the German philosophers Jürgen Habermas and Bernhard Waldenfels. In all of them the problems of otherness, alterity, exclusion and inclusion play a very important role: the otherness and the exclusion of other cultures or social groups (asylum seekers, immigrants, poor people) or entire ethnic groups (like indigenous peoples in a country like Mexico). The result of this reflection is a conception of democracy and, in general, of the political order, as an order always open to the claims and demands from otherness and alterity, in an endless game between identity and otherness that can never be completed.