89Centuries: 1st century BC - 1st century - 2nd century
- First year of Yongyuan era of the Chinese Han Dynasty.
- Pliny the Younger becomes urban quaestor until 90.
- Dacians under Decebalus engage in two wars against the Romans from AD 85 until this year.
- Legio XIII Gemina is transferred to Dacia to help in the war against Decebalus.
- Domitian suppresses a revolt in Germania Superior.
- Change of Patriarch of Constantinople from Polycarpus to Plutarch.
- Aquincum (modern Budapest) is founded.
For the number 89, see eighty-nine.