Successor of: Eumenes II Soter
- Father: Attalus I Soter
- Mother: Apollonis of Cyzicus
- First wife: name not known
- son: Aristonicus (= Eumenes III)
- Second wife: Stratonice IV, widow of Eumenes II Soter
- 220: Birth
- 197: Death of Attalus I, who is succeeded by Eumenes II Soter. Attalus II Philadelphus ('the man who loves his brother') is his elder brother's right hand man, and helps him reorganize the large territrorial conquests.
- 192: Visit to Rome, where he warns the Senate against the Seleucid king Antiochus III the Great.
- He is present during the battle of Magnesia and supports the Roman commander Manlius Vulso during his war against the Galatians.
- 183: Defeats king Prusias I of Bithynia.
- 182-179: War against king Pharnaces of Pontus; territorial gains.
- 172: During a visit to Rome, Eumenes, hostile to the Macedonian king Perseus, informs the Senate about Perseus' presumed plans to gain influence in Greece.
- On his return, Eumenes is attacked near Cirrha, and believed to be death. Attalus II becomes king and marries queen Stratonice. When Eumenes returns, Attalus cedes power.
- During the Third Macedonian War, the Romans start to distrust Eumenes and try to make Attalus king, but he is not willing to betray his brother. The cordial relations between the Romans and Attalus remain.
- 159: Death of Eumenes II Soter; he is succeeded by Attalus II, who acts as regent for Eumenes' son Attalus III, and remarries Stratonice.
- 158: Orophernes II, supported by the Seleucid king Demetrius I Soter, becomes ruler of Cappadocia
- c.156: Attalus brings back Ariarathes V Eusebes Philopator (brother of Stratonice) to his kingdom.
- 156-154: Successful war against king Prusias II of Bithynia.
- Summer 152: Attalus II, together with Ariarathes V of Cappadocia, the Egyptian king Ptolemy VI Philometor, and Rome, support Alexander I Balas, usurper in the Seleucid Empire.
- 149: Attalus supports Nicomedes, who overthrows his father Prusias II of Bithynia.
- 138: Death. Attalus II Philadelphus is succeeded by Attalus III Philometor, the son Eumenes II.
Succeeded by: Attalus III Philometor