The Chief Secretary for Ireland was a key political office in the British administration in Ireland. Nominally subordinate to the Lord Lieutenant, and officially the "Chief Secretary to the Lord Lieutenant", from the early 19th century until the end of British rule he was effectively the government minister with responsibility for governing Ireland, roughly equivalent to the role of a Secretary of State, such as the similar role of Secretary of State for Scotland. Usually it was the Chief Secretary, rather than the Lord Lieutenant, who sat in the British Cabinet. The Chief Secretary was ex officio President of the Local Government Board for Ireland from its creation in 1872.

Lord Lieutenant of Ireland, or more formally Lieutenant General and General Governor of Ireland, was the title of the chief governor of Ireland from the Williamite Wars of 1690 until the Partition of Ireland in 1922. This spanned the Kingdom of Ireland (1541–1800) and the United Kingdom of Great Britain and Ireland (1801–1922). The office, under its various names, was often more generally known as the Viceroy, and his wife was known as the vicereine. The government of Ireland in practice was usually in the hands of the Lord Deputy up to the 17th century, and later of the Chief Secretary for Ireland.