A concept in continental philosophy and critical theory, the public sphere contrasts with the private sphere, and is the part of life in which one is interacting with others and with society at large. Much of the thought about the public sphere relates to the concept of identity and identity politics.

Heidegger claims that Dasein must balance its activities in the public sphere with its private, authentic activities, but believed ultimately that engagement in the public sphere was necessary to truly be Dasein. Hannah Arendt inverted Heidegger's claim, arguing that in fact the only true and authentic self was the self in the public sphere.

Franz Fanon discusses the way in which one's identity in the public sphere and one's identity in the private sphere can become dissonant, leading to what he calls dual consciousness. His examples deal with issues of colonialism, and the way in which a colonized subject is forced to publicly adopt a foreign culture, while privately they maintain their identity as their own culture.

In contemporary thought, informed by the rise of postmodernism, questions about the public sphere have turned to questions about the ways in which hegemonic forces dictate what discourse is and is not allowable in the public sphere, and in turn dictate what can and can't be formulated as a part of one's identity. For example, the concept of heteronormativity is used to describe the way in which those who fall outside of the basic male/female dichotomy of gender or whose sexual preferences are other than heterosexual cannot meaningfully claim their identities, causing a disconnect between their public selves and their private selves. Lauren Berlant has gone so far as to argue that there is in fact no public discourse about sex or sexuality whatsoever, leaving all sexual identity in the realm of the private sphere, where it is, in her view, deadened and powerless.

Important contemporary thinkers about the public sphere include Jürgen Habermas, Michel Foucault, Louis Althusser, and Eve Sedgwick.

See also public place.