Alvise Gritti (born 29 September 1480, died 1534), whose first name may also be spelled Aloisio, Lodovico, Ludovico, Luigi or Louis (Hungarian Lajos), was a Venetian politician. He was influential in the Hungarian Kingdom under the reign of King John I of Hungary. He was also a minister of the Ottoman sultan, and regent of Hungary from 1530 to 1534. He was the natural son of Andrea Gritti, the Venetian Bailo of Constantinople during the reign of Sultan Bayezid II and who later became the Doge of Venice in 1523.
For some years Gritti's father served as the Venetian ambassador at the Ottoman court, so Gritti was born and grew up in Constantinople. His mother was Greek. Talented, he received his higher education in Venice and Padua (1496–1507/8) and by 1527 was back in Constantinople where he had his first interview with Pargalı Ibrahim Pasha, the Grand Vizier for Suleiman the Magnificent (Suleiman I). Gritti won favor with Ibrahim, who entrusted him with great responsibilities, making him a business partner.
In 1527 Gritti supported King John I of Hungary against Ferdinand I of Habsburg, who wanted the crown for himself. He soon became one of the most important allies of King John and served as ambassador between the monarch and the Turkish sultan. In 1528 the grand vizier, according to reports, planned to take him on the projected campaign into Hungary where Gritti was to get "an important archbishopric plus a piece of the archduchy of Austria once the Turks had taken them."  Lodovico stayed in the city of Buda first as King John's advisor, and then between 1530 and 1534 as regent of Hungary.
On 9 November 1533, the governor of Marano wrote to Charles V, Holy Roman Emperor, "I heard a few days ago that the Captain-General of Croatia apprehended and sent to (your brother's city of) Ljubljana two of Gritti's spies. They have confessed that Gritti, in the name of the Turkish Emperor, has made an alliance with the kings of England and France and also with several other princes against His Imperial and Royal Majesties (Charles and his brother Frederick, then King of Bohemia and the rest of Christendom. In consequence of this the armies of the Turk, consisting of about 1,500 light horse and 22,000 hackbutiers—the whole force to be paid by the king of France—are about to invade Christendom. And it is the opinion of one of the spies that Gritti himself with his confederates will invade Croatia, Slavonia, and Hungary, and try if he can conquer those countries. Meanwhile the dukes of Bavaria and Wurtemberg and the count (landgrave) of Hesse will create disturbances in Germany, and so distress Christendom that His Imperial Majesty will find himself in trouble."
- Alvise Gritti is a character in Seasons 1-3 of the 2011–14 Turkish TV series Muhtesem Yuzyil
- The Papacy and the Levant, Volume 3 (Philadelphia, 1984) by Kenneth M. Setton, p 89
- Christine Isom-Verhaaren, Allies with the Infidel, p.216. I.B.Tauris, 2011, ISBN 1848857284
- Government of the Ottoman Empire in the Time of Suleiman the Magnificent by Albert Lybyer, p 197
- Sutton, The Papacy and the Levant, Volume 3, p 301
- Calendar of State Papers, Spain, Volume 4 Part 2: 1531-1533 (1882), pp. 858-868
- Lybyer, p 62
- Peter G. Bietenholz, Thomas B. Deutscher (2003). Contemporaries of Erasmus: a biographical register.
- Albert Lybyer (1913). Government of the Ottoman Empire in the Time of Suleiman the Magnificent.
- Ferenc Szakaly (1995). Lodovico Gritti in Hungary: 1529-1534: a historical insight.