Sequenza X is a composition for trumpet and piano by Luciano Berio, the tenth in his series of pieces with this title. The work was commissioned by the Los Angeles Philharmonic for Thomas Stevens, and premiered by him on November 19, 1984. The piece is dedicated to Ernest Fleischmann, managing director of the Los Angeles Philharmonic from 1969 to 1997, who convinced Berio to write a Sequenza for trumpet, despite years of resistance to the idea. Stevens received the music only nine days before the premiere.

The trumpet is a brass instrument commonly used in classical and jazz ensembles. The trumpet group ranges from the piccolo trumpet—with the highest register in the brass family—to the bass trumpet, pitched one octave below the standard B♭ or C trumpet.