The purpose of this study was to examine the effect of accompaniment quality on the evaluation of solo instrumental performance. Undergraduate instrumental music education majors (N = 71) listened to and evaluated the accuracy and expressivity of six excerpts of Haydn's "Concerto for Trumpet in E-Flat Major," which we created by synchronizing recordings of good and bad performances of a trumpet soloist with good and bad performances of a piano accompaniment (as well as a no-accompaniment condition). Participants also chose one "best aspect of the performance" and one "aspect needing most improvement" for each excerpt. Significant main effects for accompaniment condition (good, bad, or none) and solo condition (good or bad) were found, in addition to interaction effects. Results of a Solo × Accompaniment interaction signified that participants' ratings were not independent of accompaniment condition, and this effect was moderated by the performance quality of the trumpet soloist. Additionally, participants noted different "best aspects" and "aspects needing most improvement" based on both solo performance quality and accompaniment condition.