Joscelin II of Edessa (died 1159) was the fourth and last ruling count of Edessa.
The young Joscelin was ransomed for Baldwin II, king of Jerusalem in 1124. In 1131, his father Joscelin I was wounded in battle with the Danishmends, and Edessa passed to Joscelin II. Joscelin II refused to march the small Edessan army out to meet the Danishmends, so Joscelin I, in his last act, forced the Danishmends to retreat, dying soon after.
Joscelin II ruled the weakest and most isolated of the Crusader states. In 1138 he allied with Antioch and Byzantine emperor John II Komnenos to attack Zengi, atabeg of Aleppo, the campaign ended with the unsuccessful Siege of Shaizar. Upon returning to Antioch, Joscelin exploited local sentiment against the Byzantine Empire to instigate a riot that forced John to return home.
In 1143 both John II and Fulk of Jerusalem died, leaving Joscelin with no powerful allies to help defend Edessa. In autumn 1144, Joscelin formed an alliance with Kara Aslan of the Artuqids and marched a sizable army north to assist in their struggle with Zengi. With the capital only lightly defended, Zengi redirected his army, invading and capturing Edessa itself. Joscelin fled to Turbessel, where he held the remnants of the county west of the Euphrates.
After Yarankash, a Frankish slave, assassinated Zengi in September 1146, Joscelin recaptured Edessa in October 1146. With no help from the other Crusader states, the city was again lost in November, as Joscelin's expedition was driven out by Zengi's son Nur ad-Din. The Second Crusade, called in response to the fall of Edessa, shifted its focus to Damascus. In 1150 while en route to Antioch to enlist help, Joscelin was taken prisoner by Nur-ed-Din's Turkomans. Joscelin was taken to the city of Aleppo where he was led before a hostile crowd and publicly blinded. He spent the remaining nine years of his life in captivity in a Muslim prison. He would die in the dungeons of the Citadel of Aleppo in 1159.
Agnes of Courtenay married Amalric I of Jerusalem. After her divorce from Amalric, she held the lands and incomes of the County of Jaffa.
Joscelin II's grandchildren Baldwin IV and Sibylla were in turn monarchs of Jerusalem, as was his great-grandson Baldwin V.
Joscelin III held the nominal title Count of Edessa, being in reality the lord of a small seigneurie near Acre.