Conrad of Montferrat (Italian: Corrado del Monferrato; Piedmontese: Conrà ëd Monfrà) (c. 1146 – 28 April 1192) was a nobleman, one of the major participants in the Third Crusade. He was the de facto King of Jerusalem (as Conrad I) by virtue of his marriage to Isabella I of Jerusalem from 24 November 1190, but officially elected only in 1192, days before his death. He was also the eighth Marquess of Montferrat from 1191.

Conrad was the second son of Marquess William V of Montferrat, "the Elder", and his wife Judith of Babenberg. He was a first cousin of Frederick Barbarossa, Holy Roman Emperor, as well as Louis VII of France and Leopold V of Austria.

Conrad was born in Montferrat, which is now a region of Piedmont, in northwest Italy; during the era in which he was born, it was a margraviate of the Kingdom of Italy in the Holy Roman Empire. The exact place and year are unknown. He is first mentioned in a charter in 1160, when serving at the court of his maternal uncle, Conrad, Bishop of Passau, later Archbishop of Salzburg. (He may have been named after him, or after his mother's half-brother, Conrad III of Germany.)

A handsome man, with great personal courage and intelligence, he was described in the Historia brevis occupationis et amissionis Terrae Sanctae ("A Short History of the Occupation and Loss of the Holy Land"):

Conrad was vigorous in arms, extremely clever both in natural mental ability and by learning, amiable in character and deed, endowed with all the human virtues, supreme in every council, the fair hope of his own side and a blazing lightning-bolt to the foe, capable of pretence and dissimulation in politics, educated in every language, in respect of which he was regarded by the less articulate to be extremely fluent. In one thing alone was he regarded as blameworthy: that he had seduced another's wife away from her living husband, and made her separate from him, and married her himself.

(The last sentence refers to his third marriage to Isabella of Jerusalem in 1190, for which see below.)

He was active in diplomacy from his twenties, and became an effective military commander, campaigning alongside other members of his family in the struggles with the Lombard League. He first married an unidentified lady before 1179, but she was dead by the end of 1186, without leaving any surviving issue.

In 1179, following the family's alliance with Manuel I Comnenos, Conrad led an army against Frederick Barbarossa's forces, then commanded by the imperial Chancellor, Archbishop Christian of Mainz. He defeated them at Camerino in September, taking the Chancellor hostage. (He had previously been a hostage of the Chancellor.) He left the captive in his brother Boniface's care and went to Constantinople to be rewarded by the Emperor, returning to Italy shortly after Manuel's death in 1180. Now in his mid-thirties, his personality and good looks made a striking impression at the Byzantine court: Niketas Choniates describes him as "of beautiful appearance, comely in life's springtime, exceptional and peerless in manly courage and intelligence, and in the flower of his body's strength".