Realism and idealism are two broad concepts, recurring very frequently both in philosophical and daily discourses regarding politics, as well as other domains (for instance epistemology). They are always seen as two opposing approaches towards how the world should be understood politically and how political theory should inform political actions. Although this pair of notions does not precisely single out two fully fledged ‘traditions’, in this chapter, realism and idealism will be defined as two fundamental approaches to political theorizing. Notwithstanding the significant theoretical differences within these two fundamental approaches it is possible to single out sufficient similarities to form two broad ‘families’. The chapter will proceed as follows: firstly, the main features of realism and of the idealist approach will be analysed in turn. In each section, some critiques of both realism and idealism will be addressed. Finally, some of the most recent tendencies within both families will be discussed comparatively.