The greater part of Mary Wright's compositional output is instrumental chamber music. By not aligning herself with any particular aesthetic "camp", she has maintained a unique and original voice. Nevertheless, her frequent subtle references to vernacular music and the use of theatrical elements have enabled her to appeal to a diverse audience.

While many of today's younger composers rely heavily on patterns, repetition, and groove, Mary Wright's music retains a decidedly through-composed quality. She uses drums, guitars, and synthesizers, but their roles in her pieces are often quite unexpected. The drum set in He Don't Care, for example, is intricately woven into the counterpoint, while the violin as often as not serves a rhythmic function. In her brooding, beautiful Sunflower, for voice and chamber ensemble, the keyboard synthesizer plays mostly white noise, filling the negative spaces in the deceptively simple harmonies and giving the music a subtle sculptural quality.

Dense counterpoint characterizes much of Wright's music, with her careful attention to detail keeping it just on the edge of being out of control. Sometimes dramatic and emotional content are as important as the notes. John Harbison has said of Dad Left Before You Got A Chance to Meet Him that "it's as much a psychodrama as a composition".

Mary's music is never predictable. Though completely notated, the moment form and gestural quality of Lizard Belly Moon (recorded on Bang On A Can Live 3, CRI Emergency cd672) give the impression of four guitarists improvising. Her attention to sound is painstaking. Factory presets seldom figure into her work, and she always specifies pickup and amplifier settings for her guitar parts.

With relatively few compositions in her catalogue, Mary Wright has succeeded in creating a music that is deeply personal, technically sophisticated, and both appeals to and challenges her audience.