Sergius I may refer to:
Sergius of Tella, Patriarch of the Syriac Orthodox Church in 544–546 Sergius I of Constantinople (died in 638) Pope Sergius I (died in 701), Sicilian-born pope Sergius I of Naples (died 864) Sergius I of Amalfi (died 966) Patriarch Sergius I of Moscow (1867–1944)
See also Sergius