Hippolyte Delehaye (Antwerp 19 August 1859 – Brussels 1 April 1941) was a Belgian Jesuit who was a hagiographic scholar and an outstanding member of the Bollandists, who established critical editions of texts relating to the Christian saints and martyrs that were based on applying the critical method of sound archaeological and documentary scholarship to the texts. This critical approach encountered difficulties, within the Jesuit Order, within the Holy Office and among "integralist" opponents of critical approaches.

He joined the Jesuit Order in 1876 and became a fellow of the Société des Bollandistes named for the 17th century hagiographic scholar Jean Bolland in Brussels, 1892. He was an editor of the Bibliotheca Hagiographica Graeca (1895) a repertory of Greek hagiographies, and of the Analecta Bollandiana, which was subjected to Roman censorship 1901-27, and in 1912 became the President of the Bollandists.

His major publications, works of method and synthesis that are of general use to historians, are: