The article develops a two-dimensional typology of political reasons for governments to pledge referendums on European integration when they are not obliged to do so: the first dimension is about the political level at which the strategic use of referendum pledges is targeted and it distinguishes between domestic and European reasons; the second dimension attends to the strategic mode of governments when pledging EU referendums which can either be about avoiding political losses (the defensive mode) or about realizing political gains (the offensive mode). In combination, the typology yields four ideal types of reasons for governments to commit to EU referendums: the depoliticizing; plebiscitary; red-line; and internationalist EU referendum pledges. In the empirical analysis, the article applies this typology to classify 28 cases of discretionary government commitments to EU referendums and it presents the findings of an expert survey that has been conducted for this purpose.