Bernardus Marie (Bernard) Koldeweij was a Dutch painter, draughtsman and watercolorist.

He was born in 1859 in Dordrecht, the son of shopkeeper Bernardus Johannes Koldeweij and Pauline Marie Josephine Masion. Koldeweij studied art at the Drawing Academy in Antwerp, where he was taught by Théophile de Bock, Roland Larij, Cornelis Johannes de Vogel and Johannes Gijsbert Vogel. He worked in Dordrecht and Antwerp, among other places. In 1891, when it became apparent that Koldeweij was seriously ill, he made trips to Corsica, Switzerland and Italy (Florence).

Koldeweij was a member of Teekengenootschap Pictura in Dordrecht. In Nunspeet about 1896 he was included in a group of Maurits Constantijn Lapidoth with Gerrit Haverkamp, Henri Wouters, Jan Apol, Zeegers and Jan Kleintjes. After leaving Nunspeet, he still went to Blaricum. Shortly thereafter he died in Dordrecht at the age of 39. With his painting "the Zwijndrecht ferry" Koldeweij won the small gold medal in Munich in 1897.

In 1886 and 1887 his work was exhibited together with that of Jan Veth in the Dordrecht Museum. In 1982, his work was exhibited at the Dordrecht Museum. His work is counted among the Dordrecht Impressionism.