Nikolai Petrovich Demidov-Lopukhin (Russian - Николай Петрович Лопухин-Демидов; 27 April 1836, Saint Petersburg - 18 December 1910, Korsun-Shevchenkivskyi) was a Russian nobleman and general.
The eldest son of Pyotr Grigoryevich Demidov (1807-1862) and his wife Elizaveta Nikolaevna Bezobrazova, Nikolai was a godson of Nicholas I of Russia. He joined a guards cavalry regiment in 1853 and on 20 November 1854 was promoted to Sub-Lieutenant. From 1863 to 1864 he fought in the repression of the January Uprising. In 1870 he was promoted to colonel.
After the death of his relation Pavel Petrovich Lopukhin (son of Pyotr Lopukhin) in 1873, he inherited the princely title of the Lopukhin family and added its surname to his own. He fought in the Russo-Turkish War (1877–1878) and on 30 August 1880 was promoted to major general, followed by lieutenant general in May 1890.
He married Olga Valerianovna Stolypina (1841-1926), daughter of Valerian Grigor'evič Stolypin, and they had six children: