Gaertner or Gärtner is a German surname meaning "gardener". Notable people with the surname include:
- Karl Friedrich von Gaertner (1772–1850), German botanist known as "C.F.Gaertn." or "Gaertner fils"
- Christian Gärtner (1705–1782), German merchant and astronomer, after whom is named:
- Gärtner (crater), a crater on the Moon
- 132445 Gaertner, an asteroid
- Joseph Gaertner (1732–1791), German botanist known as "Gaertn."
- Friedrich von Gärtner (1791–1847), German architect
- Gottfried Gaertner (1754–1825), German botanist known as "G. Gaertn."
- Friedrich Gärtner (1824–1905), German architectural painter
- Gustav Gärtner (1855–1937), Austrian pathologist
- Carl Gaertner (1898–1952), U.S. artist
- Belva Gaertner (1885–1965), U.S. cabaret singer and alleged murderer
- Georg Gärtner (1920–2013), German soldier
- Hildesuse Gärtner (1923–2016), German alpine skier
- Bertil Gärtner (1924–2009), Swedish Lutheran bishop of Gothenburg
- Claus Theo Gärtner (born 1943), German television actor
- Jürgen Gärtner (born 1950), German mathematician