A trend in information systems development is for globally distributed teams to use agile methods and frameworks such as Scrum. In globally distributed (GD) software development, a known challenge is effective team communication. Researchers, however, cannot evaluate effective communication in GD teams using Scrum unless they know what effective communication means in that context. This qualitative study contributes a theoretical model of effective communication in GD Scrum teams and practical guidance for practitioners. Ten industry professionals working in GD Scrum teams were interviewed to capture their understanding of effective communication. Qualitative content analysis was used to analyse the interviews and form a basis for the model and the practical guidance. This novel model consists of communication transparency, communication quality, and communication discipline, which together lead to the alignment of team understanding (i.e., a team-level shared mental model). This theoretical model lays the ground for future research into the effect of Scrum practices on communication in GD contexts, and the effect of communication on team and project success. For practitioners, this study contributes 11 practical actions that professionals recommend for improving and sustaining effective communication.