'Gunzo' (also ''Cunzo'') was a
7th century duke of the
Alamanni under
Frankish sovereignty. His residence was at ''villa Iburninga'' (today's
Überlingen) at
Lake Constance. Gunzo was the father of
Fridiburga, who was engaged to Frankish king
Sigibert II (who was murdered in
613).
Gunzo organized a synod in
Konstanz in
635, which resulted in the election of deacon
John of Grab as bishop of Constance, succeeding the deceased bishop Gaudentius. This event is the earliest certain attestation of Constance as an independent bishopric.
It is disputed whether Gunzo ruled over all of
Alemannia, or only over the eastern part. If the former is the case, he is to be identified either with
Gundoin, the founder of the
Moutier-Grandval monastery, or with the predecessor of the latter, duke Uncilin.