Obesotoma cymata is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
The length of the shell attains 23 mm, its diameter 10.5 mm.
(Original description) The shell resembles typical Obesotoma tenuilirata <small>(Dall, 1871</small>, but with a higher and more acute spire, and with 20 or more narrow axial riblets on the body whorl, obsolete on the base, and a single spiral thread at the shoulder.
This marine species occurs from Nunivak Island, Bering Sea, to the Shumagin Islands, Alaska.