The Unionist Party of Punjab during British Rule in India.

The Unionist Muslim League, also known simply as the Unionist Party was a political party based in the province of Punjab during the period of British rule in India. The Unionist Party included Muslims, Hindus, and Sikhs. The Unionists dominated the political scene in Punjab from World War I to the division of British India into India and Pakistan and the partition of Punjab in 1947.

The Unionist Party, a secular party, was formed in Punjab to represent the interests of Punjab's. Sir Sikandar Hayat Khan, Sir Fazli Husain and Sir Chhotu Ram were the co-founders of the party. Although a majority of Unionists were Muslims, a large number of Hindus and Sikhs also supported and participated in the Unionist Party.

In contrast with Congress, the Unionists supported the British Raj and contested elections for the Punjab Legislative Council and the Central Legislative Council at a time when Congress and the Muslim League were boycotting them. As a result, the Unionist Party dominated the provincial legislature for a number of years, allowing an elected provincial government to function when other provinces were governed by the direct rule.

The Muslim elements of the Unionists shared many common points with the Muslim League and followed a rather similar policy and agenda for national interests and issues, but the Unionists were virtually an independent political party in the 1920s and 1930s when the Muslim League was unpopular and divided into feuding factions. The links improved after Muhammad Ali Jinnah became the League's president in the mid-1930s and by October 1937, and then he was able to convince Sir Sikandar Hayat Khan to come to terms with him via the famous Sikandar-Jinnah Pact.

However, the rule of Unionist leader Sir Sikandar Hayat remained undisputed in Punjab and he remained Punjab's Premier (Chief Minister) from 1937 to 1942, in alliance with the Indian National Congress and the Shiromani Akali Dal, despite Jinnah's opposition to both parties. Sir Sikandar Hayat thus remained the most popular and influential politician in Punjab during his lifetime, preventing both Jinnah and Sir Muhammad Iqbal from gaining the support of a majority of Punjabi Muslims.

However, the Unionists grew closer to the All India Muslim League in the early 1940s. Sir Sikandar Hayat was one of the movers of the Pakistan Resolution that was passed in Lahore, on 23 March 1940, calling for an autonomous Muslim state or region within a larger Indian confederation; this developed into the demand for an independent Pakistan.

Sir Sikandar Hayat supported the British in the Second World War at the request of Sir Winston Churchill after all of India's political parties had refused. The British promised dominion status to India after the war. After his suspicious death, other players moved in. Sir Sikandar Hayat did not envisage partition of his beloved Punjab. When he hears the intended partition of Punjab he rejected this outright.

After Sir Sikandar Hayat death in 1942, Sir Chhotu Ram was invited to be the premier, but he declined in favor of Malik Khizar Hayat Tiwana. The Unionist Party under Khizar Hayat could not match the Sir Sikandar Hayat popularity, and with the increasing popularity and influence of Jinnah, the Unionist Party wiped out. Although it struggled on, under Khizar Hayat from late-1942 to 1946, the writing was very much on the wall.

As the demand for Pakistan grew more intense, political loyalties in Punjab were reshaped on religious lines. The Direct Action Day campaign brought the downfall of Sir Khizar Hayat ministry, which depended on Congress and Akali support; inter-community relations were effectively destroyed as communal violence across Punjab resulted in the massacre of 2 million Punjabis (world's largest massacre within short span of time) and displacement of 20 million Punjabis (largest human mass migration of known history).

With the division of British India into India and Pakistan in 1947, Punj Darayaaeab was itself partitioned between the two new countries, with Muslim-majority West Punjab is forming part of Pakistan, and the Hindu/Sikh-majority East Punjab is forming part of India. The Unionist Party's diverse pan-provincial organization was destroyed, with Muslim Unionists integrating themselves into the Muslim League; the party ceased to exist in existing in independent Pakistan.