Robert Adair may refer to:

• Robert Adair (of Hollybrook) (died 1737), Irish MP for Philipstown (Parliament of Ireland constituency) and protagonist in one version of the song "Robin Adair"
• Robert Adair (politician) (1763–1855), British diplomat
• Robert Adair, 1st Baron Waveney (1811–1886), English politician, MP for Cambridge 1847–1852 and 1854–1857
• Robert Adair (cricketer) (1876–1951), Irish cricketer
• Robert Adair (actor) (1900–1954), American actor
• Robert Adair (physicist) (born 1924), American physicist