Oud-Beijerland ( pronunciation ) is a town and municipality in the western Netherlands, in the province of South Holland. With a population of 23,683 in 2014, it is the most populous municipality on the Hoeksche Waard island. The town is located adjacent to the confluence of the Oude Maas and Spui River.
The municipality of Oud-Beijerland also includes the communities Vuurbaken and Zinkweg.
After the St. Elizabeth's flood (1421), large parts of the islands Putten and Grote Waard were lost and became clay banks and salt marshes which would be inundated at high tide and be unsuitable for habitation. In subsequent centuries, portions of land would be reclaimed.
Oud-Beijerland was formed in 1559 as "Beijerland" by Lamoral, Count of Egmont. He was granted the rights to this area in 1557 and had the land reclaimed. This new polder was named Beijerland, Moerkerken, Cromstrijen en de Greup. Circa 1624 the smaller polders Bosschenpolder and Nieuwlandpolder were added to it. Beijerland was named after Sabina of Bavaria (Dutch: Beijeren), wife of the Count of Egmont.