Saint V (French), Sint V (Dutch) or St V are the commonly used names for a holiday for freethinking university students in Brussels, Belgium. It takes place annually on 20 November and commemorates the founding of the Free University of Brussels on 20 November 1834. The day's long forms differ in the two official languages, but both are a reference to Pierre-Théodore Verhaegen, the university's founder, who notably is not a saint and was never canonized; the name was chosen instead to mock the Saint-Nicolas festivities of the rival Catholic University.

The Free University of Brussels was a university in Brussels, Belgium. Founded in 1834 on the principle of "free inquiry", its founders envisaged the institution as a free-thinker reaction to the traditional dominance of Catholicism in Belgian education. The institution was avowedly secular and particularly associated with Liberal political movements during the era of pillarisation. The Free University was one of Belgium's major universities, together with the Catholic University of Leuven and the state universities of Liège and Ghent.