Company rule in India (also known as the Company Raj, from Hindi rāj, lit. 'rule') refers to regions of the Indian subcontinent under the control of the British East India Company (EIC). The EIC, founded in 1600, established its first trading post in India in 1612, and gradually expanded its presence in the region over the following decades. During the Seven Years' War, the East India Company began a process of rapid expansion in India, which resulted in most of the subcontinent falling under its rule by 1857, when the Indian Rebellion of 1857 broke out. After the rebellion was suppressed, the Government of India Act 1858 resulted in the EIC's territories in India being administered by the Crown instead. The India Office managed the EIC's former territories, which became known as the British Raj.

The range of dates is taken to have commenced either in 1757 after the Battle of Plassey, when the Nawab of Bengal Siraj ud-Daulah was defeated and replaced with Mir Jafar, who had the support of the East India Company; or in 1765, when the Company was granted the diwani, or the right to collect revenue, in Bengal and Bihar; or in 1773, when the Company abolished local rule (Nizamat) in Bengal and established a capital in Calcutta, appointed its first Governor-General of Fort William, Warren Hastings, and became directly involved in governance. The East India Company significantly expanded its influence throughout the Indian subcontinent after the Anglo-Mysore Wars, Anglo-Maratha Wars, and Anglo-Sikh Wars. Lord William Bentinck became the first Governor General of India in 1834 under the Government of India Act 1833.

The English East India Company ("the Company") was founded in 1600, as The Company of Merchants of London Trading into the East Indies. It gained a foothold in India with the establishment of a factory in Masulipatnam on the Eastern coast of India in 1611 and the grant of the rights to establish a factory in Surat in 1612 by the Mughal Emperor Jahangir. In 1640, after receiving similar permission from the Vijayanagara ruler further south, a second factory was established in Madras on the southeastern coast. Bombay island, not far from Surat, a former Portuguese outpost gifted to England as dowry in the marriage of Catherine of Braganza to Charles II, was leased by the Company in 1668. Following the Anglo-Mughal War, the Company was allowed by Emperor Aurangzeb to establish a presence on the eastern coast as well; far up that coast, in the Ganges Delta, a factory was set up in Calcutta. Since, during this time other companies—established by the Portuguese, Dutch, French, and Danish—were similarly expanding in the region, the English Company's unremarkable beginnings on coastal India offered no clues to what would become a lengthy presence on the Indian subcontinent.

The company's victory under Robert Clive in the 1757 Battle of Plassey and another victory in the 1764 Battle of Buxar (in Bihar) consolidated the company's power and forced emperor Shah Alam II to appoint it the diwan, or revenue collector, of Bengal, Bihar, and Orissa. The Company thus became the de facto ruler of large areas of the lower Gangetic plain by 1773. It also proceeded by degrees to expand its dominions around Bombay and Madras. The Anglo-Mysore Wars (1766–1799) and the Anglo-Maratha Wars (1772–1818) left it in control of large areas of India south of the Sutlej River. With the defeat of the Marathas, no native power represented a threat for the Company any longer.

The expansion of the company's power chiefly took two forms. The first of these was the outright annexation of Indian states and subsequent direct governance of the underlying regions, which collectively came to comprise British India. The annexed regions included the North-Western Provinces (comprising Rohilkhand, Gorakhpur, and the Doab) (1801), Delhi (1803), Assam (Ahom Kingdom 1828), and Sindh (1843). Punjab, North-West Frontier Province, and Kashmir, were annexed after the Anglo-Sikh Wars in 1849-1856 (Period of tenure of Marquess of Dalhousie Governor General); however, Kashmir was immediately sold under the Treaty of Amritsar (1850) to the Dogra dynasty of Jammu, and thereby became a princely state. In 1854 Berar was annexed, and the state of Oudh two years later.^{[citation needed]}

The second form of asserting power involved treaties in which Indian rulers acknowledged the company's hegemony in return for limited internal autonomy. Since the Company operated under financial constraints, it had to set up political underpinnings for its rule. The most important such support came from the subsidiary alliances with Indian princes during the first 75 years of Company rule. In the early 19th century, the territories of these princes accounted for two-third of India. When an Indian ruler, who was able to secure his territory, wanted to enter such an alliance, the Company welcomed it as an economical method of indirect rule, which did not involve the economic costs of direct administration or the political costs of gaining the support of alien subjects.

In return, the Company undertook the "defence of these subordinate allies and treated them with traditional respect and marks of honor." Subsidiary alliances created the princely states, of the Hindu maharajas and the Muslim nawabs. Prominent among the princely states were: Cochin (1791), Jaipur (1794), Travancore (1795), Hyderabad (1798), Mysore (1799), Cis-Sutlej Hill States (1815), Central India Agency (1819), Cutch and Gujarat Gaikwad territories (1807–1820), Rajputana (1818), and Bahawalpur (1833).

The Governors-General (locum tenens) are not included in this table unless a major event occurred during their tenure.