Mitrofan Petrovich Belyayev was a Russian music publisher, outstanding philanthropist, and the owner of a large wood dealership enterprise in Russia. He was also the founder of the Belyayev circle, a society of musicians in Russia whose members included Nikolai Rimsky-Korsakov, Alexander Glazunov and Anatoly Lyadov. His surname is often transliterated as Belaieff or Belayev. In 1886 the Russian painter Ilya Repin made a portrait of Belyayev.

The Belyayev circle was a society of Russian musicians who met in Saint Petersburg, Russia between 1885 and 1908, and whose members included Nikolai Rimsky-Korsakov, Alexander Glazunov, Vladimir Stasov, Anatoly Lyadov, Alexander Ossovsky, Witold Maliszewski, Nikolai Tcherepnin, Nikolay Sokolov, Alexander Winkler among others. The circle was named after Mitrofan Belyayev, a timber merchant and amateur musician who became a music philanthropist and publisher after hearing the music of the teenage Glazunov.