Oughterside and Allerby is a civil parish in Allerdale district, Cumbria, England. In the 2011 census it had a population of 619. The north western boundary of the parish is a short stretch of coast, then, working clockwise, the parish is bordered by Hayton and Mealo to the north, Aspatria to the north east, Plumbland to the south east, Gilcrux to the south and Crosscanonby to the south west. The A596 road from Aspatria to Maryport passes through the parish, and the B5300 road follows its coastline in the north west. The main settlements in the parish are Allerby in the west and Oughterside and Prospect in the east.
There is a parish council, forming the lowest level of local government.
As of 2017[update] there are three listed buildings in the parish, all at Grade II.
Coordinates: 54°45′N 3°23′W / 54.75°N 3.39°W