This document focuses on providing guidelines on Air Traffic Controller (ATCO) Manpower Planning processes, which consolidates and builds on previous research and publications relating to ATCO Manpower Planning. One of the main benefits of this guidelines document on ATCO Manpower Planning is to help foster improved understanding of the Manpower Planning processes and components which leads to enhanced quality in the prediction, assignment and use of staff. In addition, by addressing a wide range of readers (including manpower planners, supervisors, ATCOs, senior management and staff members at all levels), the document provides transparency on the elements of Manpower Planning which should enable manpower planners to benchmark their current practices and identify areas for improvement.