The notion 'public' can have widely different meanings and, accordingly, many also understand the notion 'public theology' in different ways. Why would some who regard themselves as doing public theology prefer certain notions of 'public', while others prefer different understandings? In the first part, the article distinguishes three broad types of understanding the notion 'public'; ranging from a technical and almost prescriptive sense, following Habermas' description of the public sphere, to a vague and almost descriptive sense, following Tracy's description of all theological discourse as public. The second part serves as reminder of the similar range of possible meanings of the notion 'public theology', roughly corresponding to this wide spectrum of uses of 'public'. The third and final section then briefly reflects on the question why certain theologians prefer to do certain forms of public theology, suggesting both sociological reasons, like Tracy's 'elective affinities', as well as theological reasons; fundamentally different ways of viewing God and divine involvement in the world.