Martens is a surname. Notable people with the surname include:
- Adolf Martens (1850–1914), a German metallurgist
- Frédéric Martens (1806–1885), a French photographer
- Claire Martens (born 1987), Dutch politician
- Conrad Martens (1801–1878), an English-born artist active in Australia
- Eduard von Martens (1831–1904), a German zoologist
- Friedrich Martens (1845–1909), a Russian diplomat
- Friderich Martens (1635–1699), a German physician and naturalist
- George Martens (1874–1949), an Australian politician
- Georg Friedrich von Martens (1756–1821), a German jurist and diplomat
- Jürgen Martens (born 1959), German politician
- Lieke Martens, Dutch football player
- Ludo Martens (1946–2011), a Belgian historian and chairman of the Workers' Party of Belgium
- Ludwig Martens (1875–1948), Soviet diplomat and engineer
- Maarten Martens (born 1984), a Belgian football player
- Martin Martens (M.Martens, 1797–1863), a botanist
- Maria Martens (born 1955), a Dutch politician
- Maurice Martens (born 1947), a Belgian football player
- René Martens (born 1955), a Belgian cyclist
- Rudy Martens (born ca. 1958), a Belgian organizational theorist
- Sandy Martens (born 1972), a Belgian football player
- Theodor Martens (1822–1884), a German artist
- Wilfried Martens, (1936–2013), a Flemish Belgian politician