Konstantin Ignat'evich Krupski (1837–1897), was a Russian military officer and a nobleman of the Russian Empire who had been orphaned in 1847 at the age of nine.

He was educated and given a commission as an infantry officer in the Russian Army. Just before leaving for his assignment in Poland, he married Krupskaya's mother. After six years of service, Krupski lost favour with his supervisors and was charged with "un-Russian activities." He may have been suspected of being involved with revolutionaries. Following this time he worked in factories or wherever he could find work. Just before his death, he was recommissioned as an officer.