Alexander Onufrievich Kovalevsky (Russian: Алекса́ндр Ону́фриевич Ковале́вский, 7 November 1840 in Vorkovo, Dvinsky Uyezd, Vitebsk Governorate, Russian Empire – 1901, St. Petersburg, Russian Empire), was a Russian embryologist, who studied medicine at the University of Heidelberg and became professor at the University of St Petersburg.He was the brother of paleontologist Vladimir Kovalevsky, and the brother-in-law of the mathematician Sofya Kovalevskaya.