Rhopalocarpus randrianaivoi is a tree in the family Sphaerosepalaceae. It is endemic to Madagascar. It is named for the authors' colleague and specimen collector Richard Randrianaivo.
Rhopalocarpus randrianaivoi grows as a tree up to tall. The coriaceous leaves are elliptic in shape and measure up to long. The species is not known to have any flowers. The fleshy fruits are coloured brown. They may be spherical or two-lobed and measure up to across.
Rhopalocarpus randrianaivoi is known only from a few locations in the northeastern region of Sava. Its habitat is humid or subhumid evergreen forests from sea level to altitude.
Rhopalocarpus randrianaivoi is threatened by shifting patterns of agriculture which are causing deforestation. The species is not present in any protected areas.