Year 87 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Octavius and Cinna/Merula (or, less frequently, year 667 Ab urbe condita) and the Second Year of Houyuan. The denomination 87 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

• Lucius Cornelius Cinna is elected consul of Rome, thus returning the rule of Rome back to the populares faction.
• Sulla arrives in Greece and besieges Athens. He orders Lucius Licinius Lucullus to raise a fleet from Rome's allies around the eastern Mediterranean.
• Ostia is razed by Gaius Marius as he comes back from Africa with an army to take Rome by force.

• March 29 – Emperor Wu of Han dies after a 54-year reign in which he leads the Han dynasty (China) through its greatest expansion. The Empire's borders span from modern Kyrgyzstan in the west, to Mongolia in the north, to Korea in the east, and to northern Vietnam in the south.
• March 30 – The eight-year-old Liu Fuling becomes emperor, with Huo Guang General-in-Chief and regent.^[1]

• Antikythera mechanism manufactured.

• Lucius Munatius Plancus, Roman consul (approximate date)

• March 29 – Han Wudi, emperor of the Han dynasty (b. 157 BC)
• Apollodorus of Artemita, Greek writer
• Gaius Atilius Serranus, Roman consul and senator
• Gaius Julius Caesar Strabo, Roman politician
• Gnaeus Pompeius Strabo, Roman general and politician
• Gotarzes I, ruler (shah) of the Parthian Empire
• Lucius Cornelius Merula, Roman politician and priest
• Lucius Julius Caesar, Roman consul (killed by partisans of Gaius Marius)
• Marcus Antonius, Roman consul (executed by order of Marius and Cinna)
• Publius Licinius Crassus, Roman consul and censor (killed by Marians invading Rome)
• Quintus Ancharius, Roman politician (executed by order of Marius and Cinna)