Rolea B'ier District (Khmer: ស្រុករលាប្អៀរ) is a district (srok) in the center of Kampong Chhnang Province, in central Cambodia. The district capital is Rolea B'ier, a town located 5 kilometres south of the provincial capital of Kampong Chhnang. The district is surrounded by other Kampong Chhnang districts and in turn surrounds Kampong Chhnang District which includes the provincial capital. The Tonle Sap serves as the border of the district in the north east.