Publicity can be opposed both to privacy and to secrecy. This entry will mostly deal with the latter meaning. In everyday life, calls for greater transparency or openness in political and economic life may seem uncontroversial. Still, the precise reasons why and the extent to which publicity should be upheld are not straightforward. Moral and political philosophers, along with social scientists, have until now provided us with only fragmentary elements in this respect. We shall review here what has been gathered so far.