Maria of Montferrat (or Maria of Jerusalem) (1192–1212) was Queen of Jerusalem, the daughter of Isabella I of Jerusalem and Conrad of Montferrat. She was known in her youth as The Marquise, because of her father's title.
Isabella died shortly thereafter and Maria became queen of Jerusalem, at the age of thirteen, while her stepbrother Hugh, from the first marriage of Aimery, became King of Cyprus and married Maria's half-sister, Alice of Champagne. The half-brother of her mother, John of Ibelin, the Old Lord of Beirut, acted as regent on behalf of Maria. The regency expired in 1209, when Maria was seventeen, so the government believed it best for Maria to marry so she could secure her post as queen. The assembly of barons and prelates decided to seek advice from Philip II of France, who offered one of his followers, John of Brienne. However John was not a very rich man. To overcome his lack of fortune and to enable him to fund his sovereign obligations (court and army) King Philip and Pope Innocent III each paid him the sum of 40 000 livres.
The marriage was celebrated on 4 September 1210, then the couple were crowned King and Queen of Jerusalem on 3 October 1210 in Tyre Cathedral.