Łęczyca [wɛnˈt​͡ʂɨt​͡sa] (in full The Royal Town of Łęczyca, Polish: Królewskie Miasto Łęczyca; other names: Lenczyk, Luntschitz, German: Lentschütz, Hebrew: לונטשיץ‎) is a town of 16,594 inhabitants (as of 2004) in central Poland. Situated in the Łódź Voivodeship, it is the county seat of the Łęczyca County.

Łęczyca is one of the oldest Polish cities, mentioned in the 12th century. It was the place of the first recorded meeting of Sejm, the Polish parliament in 1182. It was the capital of the Łęczyca Duchy in the 13th century, and next it became the capital of Łęczyca Voivodeship since 14th till 18th century.

In 1331 the Teutonic Knights sacked the city during one of their repeated incursions into central Europe. A considerable number of buildings were burned down, including two churches. A few decades later, on the initiative of Kazimierz the Great, the city was walled and a castle built to the southeast of the city.

The city's prominence came to and end with the Swedish invasion of Poland when the castle was overrun and most of the city once again destroyed, and it remained in a state of crisis until the Partitions.