Alexandr Alexandrovich Fischer von Waldheim (born 20 April 1839 in Moscow, Russian Empire - died 24 February 1920 in Sochi, Russia) was a Russian Botanist. He was a director of the Saint Petersburg Botanical Garden. He was the son of Alexandr Grigorievich Fischer von Waldheim (1803 - 1884) and the grandson of Gotthelf Fischer von Waldheim.