Lille Cathedral, the Basilica of Notre Dame de la Treille (French: Basilique-cathédrale Notre-Dame-de-la-Treille de Lille), is a Roman Catholic church and basilica in Lille, France, and the cathedral of the Archdiocese of Lille. An example of Gothic Revival architecture, the cathedral is considered a national monument.

The church was built in honor of the Virgin Mary and takes its name from a 12th-century statue of the saint that has miraculous properties ascribed to it. The project of its construction, which was carried out by a commission that brought together representatives of the clergy and lay members of the upper middle class such as fr:Charles Kolb-Bernard, had a twofold objective. The first was to rebuild a large church in the heart of the city, after the destruction of the Collegiate Church of St. Peter during the French Revolution, which had housed the statue of Our Lady of the Treille for more than six hundred years. The second was to establish an episcopal see in Lille, which then belonged to the Archdiocese of Cambrai. This creation was considered essential to establish the city's status as a religious capital and to serve the growing population during the period of the Industrial Revolution. The building was therefore designated from the outset to be a future cathedral.

Its construction, which spanned nearly a hundred and fifty years, began in 1854 with the laying of a foundation stone and the launch of an international competition for the design of a building inspired by the "Gothic style of the first half of the 13th century". Of the 41 submissions made, the first two prizes were awarded to English projects. However, the idea of entrusting the construction of a church in honor of the Virgin to foreign architects of an Anglican confession raised objections. Therefore, the realization of the project fell into the hands of Lille architect Charles Leroy. The construction of the church faced many difficulties, especially to raise the necessary funds for the continuation of the work. The cathedral was built in stages under the direction of several generations of architects from 1856 to 1975. It was completed in 1999 by the installation of a modern facade, with part of the initial program having been abandoned.

Pope Pius IX granted a decree of Pontifical coronation towards the Marian statue enshrined within the church on 15 June 1874. The rite of coronation was carried out by the Archbishop of Cambrai, René-François Régnier as Papal legate on 21 June 1874. Originally a simple church, it was given the title of minor basilica by Pope Pius X on 7 October 1904. The same Pontiff on 25 October 1913, via the Papal bull “Consistotiali Decreto”, the Archdiocese of Cambrai was split to create the diocese of Lille, with the basilica serving as its new cathedral. In 2008, following the reorganization of the ecclesiastical provinces of France, the diocese of Lille was elevated to the status of metropolis and the cathedral became a metropolitan cathedral, seat of the Archbishop of Lille.