The Commander-in-Chief of the Forces, later Commander-in-Chief, British Army, or just the Commander-in-Chief (C-in-C), was (intermittently) the professional head of the English Army from 1660 to 1707 and of the British Army from 1707 until 1904. In 1904 the office was replaced with the creation of the Army Council and the appointment of Chief of the General Staff.

The English Army existed while England was an independent state and was at war with other states, but it was not until the Interregnum and the New Model Army that England acquired a peacetime professional standing army. At the Restoration of the monarchy, Charles II kept a small standing army, formed from elements of the Royalist army in exile and elements of the New Model Army, from which the most senior regular regiments of today's British Army can trace their antecedence. Likewise, Royal Marines can trace their origins back to the formation of the English Army's "Duke of York and Albany's maritime regiment of Foot" at the grounds of the Honourable Artillery Company on 28 October 1664.