 This entry began by noting that existence raises a number of deep and important problems in metaphysics, philosophy of language, and philosophical logic. The entry has examined some of those problems and surveyed a number of different accounts of existence. None of the theories surveyed is wholly satisfying and without cost. The first view proposed by Frege and Russell treats existence as a second-order property and assimilates seemingly singular existentials to general existentials.  The proposal requires descriptivism, the thesis that ordinary proper names have descriptive equivalences, which many find to be a problematic thesis. The second Meinongian view requires countenancing individuals that do not exist. We have seen the view face challenges in giving coherent and yet informative and compelling individuation principles for nonexistent individuals and all versions of the view suffer from the problem of metaphysical overpopulation. Finally, the naive view that existence is a universal property of individuals was presented. That view faced the problem of having to reject the truth of highly intuitively true singular negative existential sentences like ‘Ronald McDonald does not exist’. The view also faces difficulties in properly accounting for the interaction of quantifiers and modal and tense operators. Existence remains, then, itself a serious problem in philosophy of language, metaphysics, and logic and one connected to some of the deepest and most important problems in those areas.