Basil I (disambiguation)

Basil I the Macedonian (c. 811–886) was a Byzantine emperor and founder of the Macedonian dynasty.

Basil I may also refer to:
 * Basil I of Constantinople, surnamed Scamandrenus, Patriarch of Constantinople 970–974
 * Basil I of Bulgaria, Patriarch of Bulgaria c. 1186–c. 1232
 * Basil I of Russia (1371–1425), Grand Prince of Moscow and Vladimir 1389–1425
 * Vasilije, Serbian Patriarch in 1763–1765