The Red Fort or Lal Qila (Hindustani: [laːlqiːlaː]) is a historic fort in Old Delhi, Delhi in India that served as the main residence of the Mughal Emperors. Emperor Shah Jahan commissioned construction of the Red Fort on 12 May 1638, when he decided to shift his capital from Agra to Delhi. Originally red and white, its design is credited to architect Ustad Ahmad Lahori, who also constructed the Taj Mahal. The fort represents the peak in Mughal architecture under Shah Jahan, and combines Persianate palace architecture with Indian traditions. The Red Fort was designated a UNESCO World Heritage Site in 2007 as part of the Red Fort Complex.

The fort was plundered of its artwork and jewels during Nader Shah's invasion of the Mughal Empire in 1739. Most of the fort's marble structures were subsequently demolished by the British following the Indian Rebellion of 1857. The fort's defensive walls were largely undamaged, and the fortress was subsequently used as a garrison. On 15 August 1947, the first Prime Minister of India, Jawaharlal Nehru, raised the Indian flag above the Lahori Gate. Every year on India's Independence Day (15 August), the Prime Minister hoists the Indian tricolour flag at the fort's main gate and delivers a nationally broadcast speech from its ramparts.

The major architectural features are in mixed condition; the extensive water features are dry. Some buildings are in fairly good condition, with their decorative elements undisturbed; in others, the marble inlaid flowers have been removed by looters. The tea house, although not in its historical state, is a working restaurant. The mosque and hammam or public baths are closed to the public, although visitors can peer through their glass windows or marble latticework. Walkways are crumbling, and public toilets are available at the entrance and inside the park. The Lahori Gate entrance leads to a mall with jewellery and craft stores. There is also a museum of "blood paintings", depicting young 20th-century Indian martyrs and their stories, an archaeological museum and an Indian war-memorial museum.