Sidão or Sidao is a given name and nickname. Notable people with the name include:
Sidão (volleyball), the nickname of Sidnei dos Santos Júnior, Brazilian volleyball player Sidão (footballer), the nickname of Sidney Aparecido Ramos da Silva, Brazilian footballer Jia Sidao (1213–1275), chancellor during the late Song dynasty of China Lu Sidao (531–582), Chinese poet of the Sui dynasty