Alexander Robertson or Alex Robertson may refer to:
- Alexander Robertson (artist) (1772–1841), Scottish-American artist and co-founder of Columbian Academy of Painting
- Alexander Robertson (Canadian politician) (1838–1888), lawyer and politician from Ontario, Canada
- Alexander Rocke Robertson (1841–1881), Canadian politician
- Alexander Black Robertson (1847–1920), politician from Ontario, Canada
- Alexander D. Robertson (1849–1921), politician from Prince Edward Island, Canada
- Eck Robertson (Alexander Robertson, 1887–1975), American fiddle player
- Alex Robertson (Scottish footballer) (fl. 1902–1903), Scottish footballer
- Alex Robertson (Australian rules footballer) (1887–1915), Australian rules footballer for University
- Sir Alexander Robertson (police officer) (1896–1970), British police officer, Deputy Commissioner of Police of the Metropolis, 1958–1961
- Alexander Robertson (MP) (1779–1856), British Member of Parliament for Grampound
- Alexander Robertson (chemist) (1896–1970), British chemist
- Alexander Robertson (rugby union) (1848–1913), Scottish rugby union player
- Alexander George Morison Robertson (1867–1947), Chief Justice of the Supreme Court of Hawaii
- Alexander Robertson, the name of several chiefs of Clan Donnachaidh
- Alexander Robertson & Sons, British boat building company
- Sir Alexander Robertson (veterinary surgeon) (1908–1990), Scottish veterinarian
- Alexander Provan Robertson (1925–1995), Scottish mathematician
- Alexander Cunningham Robertson (1816–1884), British general and amateur poet
- Alexander Robertson (New York politician) (1825–1902), American businessman and politician from New York
- Alexander Robertson (footballer, born 2003), English/Scottish/Australian/Peruvian footballer