In large music ensembles, directors make countless instructional decisions on a daily basis that indicate their learning priorities and guide student learning. In particular, expert music directors (i.e., those having earned a master's degree and/or National Board Certification) have advanced problem-solving strategies and effective means of fostering student learning in their ensembles. To explore the influence of musical setting on directors' instructional decision-making, the authors examined expert choral and instrumental directors' perspectives on instructional decision-making. Forty experienced music teachers employed as either a choral or instrumental ensemble music teachers wrote open-ended responses to three scenarios, each representing different instructional challenges. Three main themes emerged related to instructional challenges: (1) Pedagogy, (2) Student Motivation, and (3) Classroom Management. Within each theme, the authors articulated multiple topics that revealed similarities and differences between the choral and instrumental settings. Understanding these comparisons and contrasts by musical setting is essential to enhancing teacher education programs. Implications include improving teachers' self-awareness and advancing professional development opportunities for both choral and instrumental music directors.