A humane and fair treatment of prisoners is of intrinsic value in itself, and is generally acclaimed to reduce prisoners’ psychological distress and misconduct in prison, and their criminal behavior after release from prison. To create a more just prison climate, scholars have emphasized the importance of correctional staff. However, there is a lack of empirical research on the relationship between correctional officers’ characteristics and prisoners’ perceptions of a just treatment in prison. Our study fills this gap in knowledge. Data were used from (a) the Prison Project, a large-scale study in which prisoners held in all Dutch remand centers were surveyed (n = 1,610) and (b) the Dutch Correctional Staff Survey 2011 (n = 690). Multilevel analyses showed that prisoners perceived their treatment in prison as more procedurally just in units where there are more female officers, where officers held more positive attitudes toward rehabilitation, and where there is a higher officer-to-inmate ratio.