Christian Ulrik Kastrup (1784 – 6 September 1850) was a Norwegian jurist, military officer and politician.
A jurist by education, from Stavanger, he worked as a military officer until 1811, when he became chief of customs in Vardø.
He was elected to the Norwegian Parliament from Søndre Bergenhus in 1821, 1822 and 1824.
Originally governing from the market town of Bergen, he moved to Lærdalsøyri in 1840, becoming the second Nordre Bergenhus county governor to actually live in the county.
This article about a Norwegian politician born in the 1780s is a stub.