John X may refer to:
Pope John X (r. 914–928) John X (archbishop of Ravenna) (r. 983–998) John X bar Shushan (r. 1063/1064–1072/1073) Pope John X of Alexandria (r. 1363–1369) John X of Antioch (Greek Orthodox, r. 2013–present) John X of Schleswig-Holstein-Gottorp
See also John 10, the tenth chapter of the Gospel of John