Konstantin Nikolayevich Bestuzhev-Ryumin (Константин Николаевич Бестужев-Рюмин; 1829 in Kudryoshki, Nizhny Novgorod Governorate – 1897) was one of the most popular Russian historians of the 19th century. He held a chair in Russian History at the University of St. Petersburg (1864–85) and was elected into the Petersburg Academy of Sciences in 1890. In 1878 he founded and gave his name to the Bestuzhev Courses, "the largest and most prominent women's higher education institution in Russia".
Bestuzhev was born into one of Russia's oldest families; Mikhail Bestuzhev-Ryumin was his uncle. He started out as a journalist, helping Andrey Krayevsky to edit the literary journal Otechestvennye Zapiski where he published numerous reviews of historical and ethnographic works. He was drawn to a moderate wing of the Slavophile movement and welcomed Nikolai Danilevsky's theories. His pupils include Alexander III of Russia, several Grand Dukes from the Romanov family, and historian Sergey Platonov.
Among Bestuzhev's works are a set of popular books on Russia's history, several monographs on medieval paleography, and the two volumes of Russian History. The latter work is considered his magnum opus. Bestuzhev was known for carefully detailing the views of other historians whilst withholding his own opinions.