Antoon Emeric Marcel De Roo (born 26 August 1936 in Roeselare; died 25 February 1971) was a Belgian ornithologist.
After his military service he went to the Republic of the Congo for three years (1962–1965) as part of development aid, where he participated in the Belgian bird ringing program in Luluabourg (now Kananga).
In 1967 De Roo described the Prigogine's greenbul (Chlorocichla prigoginei) and in 1970 the subspecies Apus barbatus serlei of the African black swift.
In 1970, the parasitologist Alex Fain described the mite species Knemidokoptes derooi , which causes beak mange in the African palm swift.
In 1975 Alexandre Prigogine named the subspecies Cyanomitra alinae derooi of the blue-headed sunbird after De Roo.