Nominalizations have received considerable interest in linguistics, but some nominalizations have also received interest from philosophers, namely nominalizations that stand for 'philosophical entities' (to use Montague's 1969 term). These include nominalizations describing events, tropes, and facts, which have a received considerable interest in the semantic and philosophical literature, present and past. This paper will focus on those nominalization and the ways in which they are able to denote entities. It will then give a case study of nominalizations of modal predicates, which have received little, if any, attention in the literature so far, nominalizations of the sort need, possibility, permission, obligation, and ability. The paper will argue that nominalizations of modal predicates require recognizing a novel ontological category of modal objects, entities that are closely related to attitudinal objects, the semantic values of nominalizations of attitude verbs (belief, claim, decision, request). The paper will give a general characterization of modal objects and discuss three semantic nominalization strategies by which modal objects can be introduced.