Fyodor Petrovich Komissarzhevsky (Russian: Фёдор Петро́вич Комиссарже́вский) (1832 – 14 March 1905) was a Russian opera singer and teacher of voice and stagecraft. A leading tenor at the Mariinsky Theatre in St. Petersburg, he created many roles in Russian operas, including the Pretender in Mussorgsky's Boris Godunov and the title role in Tchaikovsky's Vakula the Smith. He had a voice described in the Grove Book of Opera Singers as small but with a "velvety timbre" and as a singer was known for not only for his clear diction and beautiful phrasing but also for his skill as an actor. He was the father of the actress Vera Komissarzhevskaya and the director Theodore Komisarjevsky.
Komissarzhevsky was born near Kiev and after studying law at St. Petersburg University worked in the Russian Department of Taxation. However, after three years and against the wishes of his father, he gave up his career as a lawyer to study singing in Italy with Pietro Repetto. He then sang, under the name "Teodoro di Pietro", in Milan, Rome, Florence and Genoa, as well as in Odessa, Madrid, Barcelona, and even Rio de Janeiro. In 1863, while in St. Petersburg with a touring Italian opera company, his success with the audiences brought him to the attention of the inspectors of the Mariinsky Theatre, who offered him a position as leading tenor with the company. He took up his appointment with the theatre in November 1863 and went on to create many roles there, most notably, Don Juan in Dargomyzhsky's The Stone Guest (1872), the Pretender in Mussorgsky's Boris Godunov (1874), Prince Sinodal in Rubinstein's The Demon (1875), and the title role in Tchaikovsky's Vakula the Smith (1876). Later Tchaikovsky would dedicate one of his songs to him ("Say of What, in the Shade of Branches" Op. 57, No. 1). At the Mariinsky, he also sang the title role of Wagner's Lohengrin for its Russian premiere in 1873.