Sher Singh was the fourth Maharaja of the Sikh Empire. Elder of the twins of Maharaja Ranjit Singh, founder of the Sikh Empire and Maharani Mehtab Kaur. His reign began on 18 January 1840 following his assault on Lahore which ended the brief regency of Maharani Chand Kaur. He was assassinated on 15 September 1843 by Ajit Singh Sandhawalia.

The Sikh Empire was a regional power based in the Punjab region of the Indian subcontinent. It existed from 1799, when Maharaja Ranjit Singh captured Lahore, to 1849, when it was defeated and conquered by the British East India Company in the Second Anglo-Sikh War. It was forged on the foundations of the Khalsa from a collection of autonomous misls. At its peak in the 19th century, the empire extended from Gilgit and Tibet in the north to the deserts of Sindh in the south and from the Khyber Pass in the west to the Sutlej in the east as far as Oudh. It was divided into four provinces: Lahore, which became the Sikh capital; Multan; Peshawar; and Kashmir from 1799 to 1849. Religiously diverse, with an estimated population of 12 million in 1831, it was the last major region of the Indian subcontinent to be annexed by the British Empire.