National Medical Science Liaison Awareness and Appreciation Day is observed annually on March 27, recognizing Medical Science Liaisons (MSLs) worldwide. MSLs are medical professionals associated with the Medical Affairs Departments of pharmaceutical and technology companies, often holding advanced degrees in biological sciences. This day highlights the importance of these professionals, who play a crucial role in establishing relationships with Key Opinion Leaders and other healthcare providers. Typical customs may include acknowledging their contributions and raising awareness about their impact in the medical field. The day serves to appreciate the often-overlooked efforts of MSLs in facilitating meaningful discussions and providing valuable clinical and educational insights.