Professionalism skills (PS) including communication, teamwork, and lifelong learning are recognized as core veterinary graduate competencies. However, consensus remains limited regarding which PS are essential and how they should be taught and assessed. More recently, professionalism has also been conceptualized as a longitudinal, identity-forming process extending beyond the acquisition of discrete skills. This study aimed to provide a multinational overview of how veterinary teaching institutions teach and assess PS, and to identify factors influencing the sustainability of professionalism curricula. A mixed-methods study was undertaken to address these aims. Quantitative data were collected through a survey examining current PS teaching, assessment practices, and implementation challenges. Qualitative data were gathered through focus groups and individual interviews, with participants recruited across six Council on International Veterinary Medical Education regions. In total, 95 survey responses were analyzed. Most respondents (93%) reported that PS are currently embedded in their curricula, 3% planned to introduce them within 5 years, and 4% reported no inclusion. Among institutions delivering PS, 44% used a hybrid delivery model combining standalone modules with integration across existing courses. Communication skills were the most frequently taught and were commonly delivered using interactive and teaching-led approaches. Ethics and welfare, along with evidence-based veterinary medicine, were most often assessed through written assessments. Barriers to sustaining PS programs included inadequate educator training (46%), limited curriculum space (44%), and insufficient faculty engagement (39%). Five focus groups and five interviews were conducted. Thematic analysis identified the importance of educational champions, institutional support for curriculum change, stakeholder perspectives, and the influence of the hidden curriculum. Participants emphasized the need for educator support and networks to sustain professionalism within the curriculum. This study provides the first multinational overview of PS education in veterinary curricula, underscoring the importance of educator support and institutional approaches to sustain professionalism as a core, identity-forming component of veterinary education.