FKBP51, also known as FK506-binding protein 51, is a molecular chaperone and scaffolding protein with significant roles in regulating hormone signaling and stress responding. Genetic variants in FKBP5, which encodes FKBP51, have been implicated in a growing number of neuropsychiatric disorders, which has spurred efforts to target FKBP51 therapeutically. However, the molecular mechanisms by which FKBP51 influences the pathways affected in these disorders are not fully understood. Protein changes in Fkbp5 KO mice, as measured by histology and proteomics, revealed alterations in a brain region- and sex-dependent manner.