The performance assessment process of public servants, in countries with civil services still in development, usually appears as a formality, instead of a key input of the strategic management process. This situation reduces its legitimacy perception among key organizational actors, leading to a vicious circle in which performance is neither informative nor binding, nor generates positive incentives towards greater performance. This article quantitatively explores the determinants of legitimacy of the performance assessments among Colombian public officials at the subnational level, using data from a large survey of public servants. The authors find that, although transparency portrays a mixed relationship with legitimacy, the role that the managers play, and the level of individual/organizational assessment alignment, are positive determinants of the levels of legitimacy of the performance management system.