''Pediasia contaminella'' is a species of moth in the family Crambidae described by Jacob Hübner in 1796. It is found in almost all of Europe, Asia Minor, the Caucasus, Transcaucasia, Iraq, Iran, the Kopet Dagh and Minusinsk.
The wingspan is 17–19 mm. Adults are on wing in July and August.
The larvae feed on ''Poa'' species and ''Festuca ovina''. They live in a silken tube.