The role of a scrum master in agile teams is to facilitate the scrum process and ensure adherence to agile principles. They act as a servant leader, supporting the development team by removing impediments, organizing sprint meetings, and fostering a collaborative environment. The scrum master also acts as a liaison between the development team and stakeholders, ensuring clear communication. Their focus is on maintaining the flow of work and encouraging best practices in software development, ultimately helping the team improve productivity and deliver quality products on time.