Victor Yakovlevich Bunyakovsky (Russian: Виктор Яковлевич Буняковский; December 16 [O.S.December 4] 1804, Bar, Ukraine, Russian Empire – December 12 [O.S. November 30] 1889, St. Petersburg, Russian Empire) was a Russian mathematician, member and later vice president of the Petersburg Academy of Sciences.

He worked in theoretical mechanics and number theory (Bunyakovsky conjecture), and is credited with an early discovery of the Cauchy - Schwarz inequality, proving it for the infinite dimensional case in 1859, many years prior to Hermann Schwarz's works on the subject.