The Lords Justices were deputies who acted collectively in the absence of the chief governor of Ireland as head of the executive branch of the Dublin Castle administration. Lords Justices were sworn in at a meeting of the Privy Council of Ireland.

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.