Lord O'Neill may refer to:
Baron O'Neill, a title in the Peerage of the United Kingdom created in 1868 Viscount O'Neill, a title in the Peerage of Ireland created in 1795 Earl O'Neill, a title in the Peerage of Ireland created in 1800 Martin O'Neill, Baron O'Neill of Clackmannan (1945–2020), Scottish politician Jim O'Neill, Baron O'Neill of Gatley (born 1957), British economist Terence O'Neill, Baron O'Neill of the Maine (1914–1990), Prime Minister of Northern Ireland from 1963 to 1969
See also Baroness O'Neill (disambiguation) O'Neill baronets O'Neill dynasty