Adult hippocampal neurogenesis is suppressed by exposure to chronic stress or exposure to the stress hormone glucocorticoids (GCs). In vitro, treatment of neural precursor cells (NPCs, the multipotent stem cells of the hippocampal neurogenic niche) with GCs induces a pro-oligodendrogenic transcriptional program and results in a shift in differentiation from a neuronal to oligodendrocytic fate. In the adult dentate gyrus, one week of restraint stress or GC exposure induced a similar increase in pro-oligodendrogenic transcription program and increase in newborn oligodendrocytes. We examined the effects of early life stress on oligodendrogenesis and associated changes in white matter. Perinatal exposure to stressful environment or GCs lead to similar increases in white matter and myelin-related genes. Differential maternal care resulted in changes in white matter in several brain regions including the hippocampus and corpus callosum. Together, these results suggest a novel model in which stress may alter brain function by promoting oligodendrogenesis, thereby altering the cellular composition and white matter structure of the brain.