Unio mancus is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.

[2][3] This species can be found from northeast Spain throughout the Mediterranean zone, northeast Africa and in the Middle East.

[4] It is present in Austria, Bosnia and Herzegovina, Croatia, Cyprus, France, Greece, Italy, Lebanon, Montenegro, Slovenia, Spain, Switzerland, Syria and Turkey.

[1] Shells of Unio mancus usually reach a size of 55–65 millimetres (2.2–2.6 in), with a maximum of 10 centimetres (3.9 in).

[5] These freshwater mussels have a dark brown or yellowish-green periostracum.