Saint Poppo (Deinze, 977 – Marchiennes, 25 January 1048) was a knight of noble descent who turned to a monastic life after experiencing a spiritual conversion.

The Vita Popponis, the biography of Poppo, was written shortly after his death by the monk Onulf and the abbot Everhelm of the Abbey of Hautmont.

He was about to marry a lady of noble family, when a flame suddenly burst out of the sky late at night and kept his lance radiating.

In 1020, the German emperor Henry II appointed Poppo Abbot of the Abbeys of Stavelot and Malmedy (in Lower Lorraine, now Belgium).

The emperor placed several imperial monasteries under Poppo's control or supervision, such as Limburg an der Hardt, Echternach, St. Gislen, Weissenburg, St. Gall, Hersfeld, Waulsort, Hautmont and Hastières.