The All-India Muslim League (AIML), commonly referred to as the Muslim League or simply the League, was a Muslim political party in the British Raj. Founded in 1906 in Dacca, Bengal Presidency (present-day Bangladesh) with the goal of securing Muslim interests in colonial India, it successfully led the Pakistan Movement, establishing a separate Muslim homeland following British exit from the subcontinent.

The party arose out of the need for the political representation of Muslims in British India, especially during the Indian National Congress-sponsored massive Hindu opposition to the 1905 partition of Bengal. During the 1906 annual meeting of the All-India Muslim Education Conference held in Israt Manzil Palace in Dacca, the Nawab of Dacca, Khwaja Salimullah, forwarded a proposal to create a political party which would protect the interests of Muslims in British India. He suggested the political party be named the 'All-India Muslim League'. The motion was unanimously passed by the conference, leading to the official formation of the All-India Muslim League in Dacca. It remained an elitist organisation until 1937, when the leadership, under the command of Muhammad Ali Jinnah, began mobilising the Muslim masses, which turned the League into a popular organisation.

The Muslim League passed the Lahore Resolution in 1940, laying the framework for the Pakistan Movement and arising as a decisive political force in the Muslim-majority provinces in the 1940s. It asserted the two-nation theory, and with a landslide victory, attaining 87 percent of all Muslim seats, in the 1946 provincial elections, it was the primary driving force behind the formation of Pakistan as a Muslim homeland in 1947.

After the Partition of India and the establishment of Pakistan, the All-India Muslim League was formally disbanded in India. The League was officially succeeded by the Pakistan Muslim League, which eventually split into several political parties. Other groups diminished to a minor party, that too only in the Kerala state of India. In Bangladesh, the Muslim League was revived in 1976, but it was reduced in size, rendering it insignificant in the political arena. In India, a separate independent entity called the Indian Union Muslim League was formed, which continues to have a presence in the Indian parliament to this day.

With the sincere efforts by the pioneers of the Congress to attract Muslims to their sessions, the majority of the Islamic leadership, with the exception of few scholars (like Sir Syed Ahmed Khan and Syed Ameer Ali who focused more on Islamic education and scientific developments), rejected the notion that India has two distinct communities to be represented separately in Congress sessions.

Syed Ahmad Khan, in 1888, at Meerut, said, "After this long preface I wish to explain what method my nation — nay, rather the whole people of this country — ought to pursue in political matters. I will treat in regular sequence of the political questions of India, in order that you may have full opportunity of giving your attention to them. The first of all is this — In whose hands shall the administration and the Empire of India rest? Now, suppose that all English, and the whole English army, were to leave India, taking with them all their cannon and their splendid weapons and everything, then who would be rulers of India? Is it possible that under these circumstances two nations — the Mahomedans and the Hindus — could sit on the same throne and remain equal in power? Most certainly not. It is necessary that one of them should conquer the other and thrust it down. To hope that both could remain equal is to desire the impossible and the inconceivable."

In 1886, Sir Syed founded the Muhammadan Educational Conference, but a self-imposed ban prevented it from discussing politics. Its original goal was to advocate for British education, especially science and literature, among India's Muslims. The conference, in addition to generating funds for Sir Syed's Aligarh Muslim University, motivated the Muslim upper class to propose an expansion of educational uplift elsewhere, known as the Aligarh Movement. In turn, this new awareness of Muslim needs helped stimulate a political consciousness among Muslim elites, For a few of them, many years after the death of Sir Syed Ahmad Khan the All-India Muslim League was formed in Dhaka, Bangladesh.

The formation of a Muslim political party on the national level was seen as essential by 1901. The first stage of its formation was the meeting held at Lucknow in September 1906, with the participation of representatives from all over India. The decision for the re-consideration to form the all-Indian Muslim political party was taken and further proceedings were adjourned until the next meeting of the All India Muhammadan Educational Conference. The Simla Deputation reconsidered the issue in October 1906 and decided to frame the objectives of the party on the occasion of the annual meeting of the Educational Conference, which was scheduled to be held in Dhaka. Meanwhile, Nawab Salimullah Khan published a detailed scheme through which he suggested the party to be named All-India Muslim Confederacy.^{[citation needed]}