Christiaan is a Dutch, Flemish and Afrikaans male given name. An archaic spelling of the name was Christiaen with "ae" to indicate the long sound "a". People with the name include:

• Christiaan van Adrichem (1533–1585), Dutch Catholic priest and theological writer
• Christiaan Andriessen (1775–1846), Dutch painter
• Christiaan Bailey (born 1981), American surfer
• Christiaan Bakkes (born 1965), South African writer
• Christiaan Bangeman Huygens (1772–1857), Dutch diplomat and civil servant
• Christiaan Barnard (1922–2001), South African cardiac surgeon known for his heart transplants
• Christiaan Basson (born 1982), South African golfer
• Christiaan Berger (1911–1965), Dutch sprinter
• Christiaan Beyers (1869–1914), South African Boer general during the Second Boer War
• Christiaan Bezuidenhout (born 1994), South African golfer
• Christiaan Frederick Beyers Naudé (1915–2004), South African cleric, theologian, and anti-apartheid activist
• Christiaen Jansz van Bieselingen (1558–1600), Dutch genre and portrait painter
• Christiaan Boers (1889–1942), Dutch Royal Netherlands Army captain during World War II
• Christiaan Both (1895–1977), Dutch sport shooter
• Christiaan Both (ecologist) (born 1969), Dutch ecologist
• Christiaan Brosch (1878–1969), Dutch sport shooter
• Christiaan Bruil (born 1970), Dutch badminton player
• Christiaan Brunings (1736–1805), Dutch hydraulic engineer
• Christiaan Cicek (born 1988), Dutch football striker
• Christiaan Coevershoff (1595–1659), Dutch painter
• Christiaan Cornelissen (1864–1942), Dutch syndicalist writer, economist, and trade unionist
• Christiaen van Couwenbergh (1604–1667), Dutch historical/allegorical painter
• Christiaan de Bruin (born 1990), South African rugby player
• Christiaan de Wet (1854–1922), South African Boer general, rebel leader and politician
• Christiaan De Wilde (born 1960s), Belgian businessman
• Christiaan du Toit (1901–1982), South African military commander
• Christiaan Eijkman (1858–1930), Dutch physician, physiologist and Nobel Prize laureate
• Christiaan Justus Enschedé (1788–1829), Dutch newspaper editor and printer
• Christiaan Freeling (born 1947), Dutch game designer and inventor of abstract strategy games
• Christiaan Willem Fokma (1927–2012), Dutch sculptor and ceramist
• Christiaan van der Goes (1530s–1600), Dutch nobleman, schout of Delft
• Christiaan Groepe (1789–1886), Khoi military leader in the Cape Colony
• Christiaan Harmse (born 1973), South African hammer thrower
• Christiaan Heij (born 1950s), Dutch mathematician
• Christiaan Hendrik Muller (1865–1945), South African Boer War general
• Christiaan Huijgens (1897–1963), Dutch long-distance runner
• Christiaan Huygens (1629–1695), Dutch physicist, mathematician, astronomer and inventor
• Christiaan Jonker (born 1986), South African cricketer
• Christiaan Josi (1768–1828), Dutch engraver and art dealer
• Christiaan Kok (born 1971), Zimbabwean cricketer
• Christiaan Kriens (1881–1934), Belgian-born American composer, pianist, violinist and conductor
• Christiaan Emil Marie Küpper (1883–1931), Dutch artist, founder of De Stijl, better known as "Theo van Doesburg"
• Christiaan Kuyvenhoven (born 1985), Dutch pianist
• Christiaan Lans (1789–1843), Dutch colonial head of the Dutch Gold Coast 1834-36
• Christiaan Frederik Louis Leipoldt (1880–1947), South African poet, dramatist, medical doctor, reporter and food expert
• Christiaan van Lennep (1887–1955), Dutch tennis player
• Christiaan Lindemans (1912–1946), Dutch double agent during the Second World War
• Christiaan Luyckx (1623–c.1675), Flemish still life painter
• Christiaan Meyer (born 1994), South African rugby player
• Christiaan Moltzer (1875–1945), Dutch sport shooter
• Christiaan Monden (born 1975), Dutch sociologist
• Christiaan Müller (1690–1763), German-born Dutch organ builder
• Christiaan Nagel (born 1982), South African-born British street artist
• Christiaan Neumeier (1921–1991), Dutch rower
• Christiaan Benjamin Nieuwenhuis (1863–1922), Dutch photographer in the Dutch East Indies
• Christiaan Offringa (fl.2001–2005), Dutch curler
• Christiaan Hendrik Persoon (1761–1836), Dutch mycologist
• Christiaan Pförtner (born 1966), German football midfielder
• Christiaan van Pol (1752–1813), Dutch flower painter
• Christiaan Roets (born 1980), South African-born Welsh rugby player
• Christiaan Scholtz (born 1970), South African rugby player
• Christiaan Sepp (c.1710–1775), German-born Dutch entomologist and artist
• Christiaan Slieker (1861–1945), Dutch early film exhibitor
• Christiaan Snouck Hurgronje (1857–1936), Dutch scholar of Oriental cultures and languages
• Christiaan Snyman (born 1996), Namibian cricketer
• Christiaan Steyn (1897–?), South African sprinter
• Christiaen Striep (1634–1673), Dutch still-life painter
• Christiaan Timmermans (born 1941), Dutch law professor and judge.
• Christiaan Tonnet (1902–1946), Dutch equestrian and modern pentathlete
• Christiaan Tonnis (born 1956), German symbolist/realist painter, draftsman, and video artist
• Christiaan Maurits van den Heever (1902–1957), Afrikaans novelist, poet, essayist, and biographer
• Christiaan Van Vuuren (born 1982), Australian actor and video blogger
• Christiaan Varenhorst (born 1990), Dutch beach volleyball player
• Christiaan van Velzen (born 1932), Dutch sport shooter
• Christiaen van Vianen (1598–1671), Dutch silversmith and draughtsman
• Christiaan Viljoen (born 1961), South African tennis player