Purpose: Sustainability has emerged as a key concept in 21st-century education. The purpose of this paper is to identify faculty's behavior and barriers to incorporating sustainability in business school classrooms and suggest potential ways to tackle them. Design/methodology/approach: This study uses focus groups and interviews with faculty at a European business school using the theory of planned behavior (TPB) to explore their beliefs and practices in incorporating sustainability in the classroom. Findings: The results show that business school faculty have a strong awareness of sustainability and a desire to incorporate it into the classrooms. Recommendations for deans and curriculum creators are proposed to reduce obstacles to successful implementation. Originality/value: The perceptions of faculty, a key agent of change in the incorporation of sustainability in the classroom, are analyzed, and practical steps to support them are suggested through the use of a TPB framework.