Martens is a surname. Notable people with the surname include:
Adolf Martens (1850–1914), a German metallurgist
Bob Martens (born 1961), a Dutch-born architect living in Austria
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
Harald Martens, a German herpetologist
Jochen Martens (born 1941), a German zoologist
Koen Martens, a Belgian carcinologist
Ludo Martens (born 1946), a Belgian historian and chairman of the Workers' Party of Belgium
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
