Isabella of Jerusalem (c. 1170-1205) was Queen of Jerusalem from 1192 to 1205. She was the daughter of Amalric I of Jerusalem and Maria Comnena, a grandneice of Byzantine emperor Manuel I Comnenus.

She was described by the poet Ambrose as "exceedingly fair and lovely". A marriage was arranged for her with Humphrey IV of Toron in 1183, but on their wedding night the castle was attacked by the forces of Saladin. Humphrey's mother, Stephanie de Milly, sent a message to Saladin telling him of the recent wedding and reminding him of their shared history. According to the chronicler Ernoul:

"[Stephanie] sent to Saladin bread and wine, sheep and cattle in celebration of her son's wedding, reminding him that he used to carry her in his arms when she was a child and he was a slave in the castle. And when Saladin received these gifts he was exceedingly delighted and gave thanks to those who brought them to him, asking where the bride and bridegroom were staying: their tower was pointed out to him. Thereupon Saladin gave out orders throughout his army that no attack should be directed at this tower."

In 1192 later Isabella was divorced from Humphrey against her will and married Conrad of Montferrat. Conrad had argued that her marriage to Humphrey was invalid because she was underage at the time; by virtue of his marriage to Isabella, Conrad became the closest male relative to the royal family and succeeded as King of Jerusalem. He soon died under mysterious circumstances, stabbed to death by the Hashshashin, while Isabella was pregnant with the future Maria of Montferrat, and the succession to the throne was disputed. She hid herself in the city of Tyre, which was both her largest city and the best defended. Help arrived in the form of Count Henry II of Champagne, a French nobleman who was the nephew of both the King of England and the King of France. It was his uncle Richard the Lion-Hearted who sent him to Tyre as his representative. The people of Tyre were reportedly so taken by his youth and handsomeness that they shouted that he should marry their princess; Isabella herself encouraged the idea. Henry and Isabella were married in short order, while she was still pregnant with Conrad's child. Imad ad-Din al-Isfahani, a Muslim chronicler, who attended the marriage, wrote:

"Henry of Champagne married the Marquis' wife on the same night, maintaining that he had first right to the dead man's wife. She was pregnant, but this did not prevent himself uniting himself with her, something even more disgusting than the coupling of the flesh. I asked one of their courtiers to whom paternity would be awarded and he said: "It will be the Queen's child." You see the licentiousness of these foul Unbelievers!"

Henry died in 1197 when he fell out of a window. They had two daughters, Alice (born 1196) and Philippa of Champagne (b.1197). While married to Henry it was retroactively decided that her marriage to Humphrey was not in fact invalid, but as Humphrey had died in the meantime, Isabella was married for a fourth time to Amalric II of Jerusalem (also Amalric I of Cyprus), brother of Guy of Lusignan. He died in 1205, shortly before his wife. They had two daughters, Sybilla and Melisende of Lusignan, and one son, Amaury (1201-1205).

On her death in 1205, she was succeeded by her daughter Maria of Montferrat.