The Concert Fantasia in G, Op. 56, for piano and orchestra, was written by Pyotr Ilyich Tchaikovsky between June and October 1884. It was premiered in Moscow on 6 March [O.S. 22 February] 1885, with Sergei Taneyev as soloist and Max Erdmannsdörfer conducting. The Concert Fantasia received many performances in the first 20 years of its existence. It then disappeared from the repertoire and lay virtually unperformed for many years, but underwent a revival in the latter part of the 20th century.

This work is written in two movements and lasts approximately 30 minutes.

Tchaikovsky had voiced his dislike for the sound of piano and orchestra while writing his Second Piano Concerto with his isolating the soloist from the orchestra as much as possible. Tchaikovsky scholar David Brown notes that the middle section of the quasi Rondo of the Fantasia, written for piano solo, "was the logical goal toward which this precedent had pointed". This gives the section the appearance of a cadenza while actually being based on new material. This cadenza substitutes for the development section in sonata form.

The Fantasia is scored for piano solo plus the following:

Woodwinds

Brass

Percussion

Strings