Orthosie (pron.: // or-THOS-ə-ee or // or-THOH-see; Greek: Ορθωσία), also known as Jupiter XXXV, is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation S/2001 J 9.
Orthosie is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 20,568 Mm in 602.619 days, at an inclination of 142° to the ecliptic (143° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2433.
Orthosie belongs to the Ananke group, retrograde irregular moons which orbit Jupiter between 19.3 and 22.7 Gm, at inclinations of roughly 150°.