Robert Traill or Trail may refer to:

• Robert Traill of Greyfriars (1603–1678), minister of Greyfriars, Edinburgh and refugee in Holland
• Robert Traill (Scottish minister) (1642–1716), minister in Kent, author and prisoner on the Bass Rock
• Robert Traill (Irish clergyman) (1793–1847), Church of Ireland clergyman
• Robert Henry Traill or Roy Traill (1892–1989), New Zealand wildlife ranger
• Robert Trail (moderator) (1720–1775), Scottish minister

• Robert Traill Spence Lowell (1816–1891), American clergyman
• Robert Traill Spence Lowell IV (1917–1977), American poet