Robert O'Callaghan may refer to:
Robert O'Callaghan (British Army officer) (1777–1840), member of the Parliament of Ireland for Bandonbridge, 1798–1801 Robert O'Callaghan (politician, born 1710) (1710–1761), Irish politician, member of the Parliament of Ireland for Fethard, Tipperary, 1755–1760 Robert Elliott O'Callaghan, (1855–1936), English vegetarianism activist See also Robert Callahan (disambiguation)