The aim of this study was to examine the effects of asynchronous (background) music on senior students' motivation and lesson satisfaction at the situational level. A counterbalanced mixed-model design was employed with two factors comprising condition (three levels) and gender (two levels). Two hundred students (82 boys, 118 girls; M age = 16.3 years) volunteered to participate in the study. A lesson was developed and delivered under three experimental conditions: a) teacher-selected music condition; b) student-selected music condition; and c) a no-music control condition. Mixed-model 3 (Condition) × 2 (Gender) ANOVAs were applied to examine the effects of experimental manipulations. No Condition × Gender interaction was observed, although there was a main effect for Condition. When the lesson was delivered under the two music conditions, students scored significantly higher in lesson satisfaction, intrinsic motivation, identified regulation and reported lower scores for external regulation and amotivation. The present results support the notion that the use of background music has potentially positive effects on students' lesson satisfaction and intrinsic motivation, although neither gender nor who selected the music (teacher vs. students) had any moderating influence on the results.