Toivo Ilmari Hannikainen (19 October 1892, Jyväskylä – 25 July 1955, Kuhmoinen) was a Finnish composer. Hannikainen was the son of Pekka Juhani Hannikainen and the brother of Väinö Hannikainen, both of whom were composers and of Tauno Hannikainen who was a conductor. After studying at the University of Helsinki (1911–14), he became a pupil of Franz Schreker at the Musikakademie in Vienna, and continued his studies with Alexander Siloti in Saint Petersburg (1915–17) and with Alfred Cortot in Paris (1919). Returning to Finland, he taught piano at the Helsinki Conservatory and later gained a Professorship at the Sibelius Academy.