Bernold of Constance (c. 1054–Schaffhausen, September 16, 1100) was a chronicler and writer of tracts, and a defender of the Church reforms of Pope Gregory VII.
From his writings comes the well known statement that ambassadors of the Byzantine Emperor Alexius I appeared at Piacenza to drum support for the military campaigns against the Seljuq Turks.
He wrote seventeen surviving tracts which are mostly apologetics for the pope's policy, defences of papal supremacy or vindications of men who advocated or enforced it in Germany.
Of broader interest is Bernold's chronicle, Chronicon, the latter part of which is a terse record of contemporary events by a knowing and intelligent observer in the extreme Papal camp.
Bernold was the author of Micrologus de ecclesiasticis observationibus (c. 1085), a lengthy commentary on the papal liturgy that became an important medieval liturgical treatise.