Theodor Bubeck (January 27, 1866–January 12, 1910) was a Russian organist, composer, and teacher of German origin. He was born in Stuttgart, the son of music teacher and conductor Christoph Friedrich Bubeck, and the brother of organist and choirmaster Gotthold Bubeck.
He studied at the Stuttgart Conservatory and then at the Moscow Conservatory, where he completed organ studies with L. I. Betting in 1895 and composition studies with Sergei Taneyev and Mikhail Ippolitov-Ivanov in 1898. A few years later, he joined the conservatory as a professor of organ.
Bubeck performed as an organist in concerts and held posts as organist at Moscow’s Reformed Church and piano teacher at the Lyceum of the Tsarevich Nicholas. He also gave private lessons and worked as a music critic for a German-language newspaper in Moscow. In 1905, he studied with Charles-Marie Widor in Paris. From 1905 to 1909, he taught organ and composition at the Moscow Conservatory as an associate professor, receiving the title of professor in 1909.
His published works include the orchestral and organ symphonic poem Sister Beatrice, based on a work by Maurice Maeterlinck and performed in 1908; a polonaise for orchestra; organ pieces including a Meditation and a Fantasy and Fugue in F-sharp minor, dedicated to Widor; piano pieces; and romances setting poems by Mikhail Lermontov and Glafira Galina. He died in Moscow on January 12, 1910, and was buried at Vvedenskoye Cemetery.