Gartner, Inc. is an American marketing, market research and advisory firm providing information technology related insight headquartered in Stamford, Connecticut, United States. It was known as Gartner Group, Inc until 2001.

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 (born 1923), German alpine skier
• Bertil Gärtner (1924-2009), Swedish Lutheran bishop of Gothenburg
• Claus Theo Gärtner (born 1943), German television actor