Robert Stewart may refer to:
Nobility and politics
- Robert II of Scotland (1316–1390), King of Scots
- Robert III of Scotland (c. 1340–1406), King of Scots, son of the above
- Robert Stewart, 1st Earl of March (c. 1515–1586), 1st Earl of March, Scottish nobleman
- Robert Stewart, 1st Earl of Orkney (1533–1593), illegitimate son of James V, King of Scotland
- Robert Stewart, 1st Marquess of Londonderry (1739–1821), Irish politician and landowner
- Robert Stewart, Duke of Albany (c. 1340–1420), Scottish royal, regent to three Scottish monarchs
- Robert Stewart, Master of Atholl (died 1437), Scottish nobleman of royal descent, great-grandson of Robert II
- Robert Stewart, Viscount Castlereagh (1769–1822), Irish politician
- Robert Stewart (Australian politician) (1831–1908), member of the Queensland Legislative Assembly
- Robert Stewart (Canadian politician) (1850–1925)
- Robert Stewart (New South Wales politician) (1816–1875), New South Wales colonial politician
- Robert Stewart (Prince Edward Island politician), (1731-1787), first Speaker of the Legislative Assembly of Prince Edward Island
- Robert Desmond Stewart (born 1949), Northern Irish politician
- Robert Marcellus Stewart (1815–1871), governor of Missouri
Sports
- Robert Stewart (American football) (born 1967), arena football player
- Robert Stewart (American football coach), American football coach for Washburn University
- Robert Stewart (cricketer) (1856–1913), South African batsman
- Robert Stewart (sailor) (1906–1988), New Zealand yachtsman
Business
- Robert Stewart (designer), Scottish designer
- Robert Stewart (entrepreneur) (1917-2006), American entrepreneur and founder of GMA Network
- Robert Stewart (industrialist) (born 1940), New Zealand industrialist knighted in 2014