The following article canvasses and evaluates the most prominent approaches to ontological commitment. It starts with Quinean approaches that focus on the existential quantifier and the values of the variables. It then contrasts Quinean approaches with more general entailment approaches that drop the preoccupation with the quantifier. It then considers a strengthening of the entailment approach that requires that ontological commitments of a theory be truthmakers for that theory. It then steps back to examine how, and to what extent, the notion of ontological commitment can be applied to ordinary language. The article concludes by considering less orthodox views associated with Frege and with Carnap.