Robert Ker may refer to:

• Robert Ker, 1st Earl of Roxburghe (c. 1570–1650), Scottish nobleman
• Robert Ker of Kersland (1634–1680), Scottish Covenanter
• Robert Ker, 3rd Earl of Roxburghe (c. 1658–1682), Scottish nobleman
• Robert Ker, 4th Earl of Roxburghe (c. 1677–1696), Scottish nobleman
• Robert Ker, 2nd Duke of Roxburghe (c.  1709–1755), Scottish nobleman
• Robert Ker (auditor general) (1824–1879), auditor general of the Colony and then the Province of British Columbia

• Robert Kerr (disambiguation)
• Robert Ker Porter