Alexius I (disambiguation)

Alexius I or Alexios I Komnenos (1048–1118), was Byzantine Emperor.

Alexius I may also refer to:


 * Alexius of Constantinople, Ecumenical Patriarch in 1025–1043
 * Alexios I of Trebizond (c. 1182–1222), Emperor of Trapezunt
 * Alexis of Russia (1629–1676), second Russian tsar of the Romanov dynasty
 * Patriarch Alexy I of Moscow (1877–1970), 13th Patriarch of Moscow