Increases in mesopredator populations due to habitat fragmentation may have cascading effects on prey (e.g., songbirds) and may increase competitive interactions within the guild. We compared micro- and macrohabitat selection of the Virginia opossum (Didelphis virginiana) between areas with and without removal of the raccoon (Procyon lotor), a putative competitor, in a fragmented habitat in north-central Oklahoma. Live trapping conducted in 1998–2001 resulted in 482 total captures of opossums. Vegetation was sampled in summer (April–August) around trapsites associated with 235 of those captures. Ordination analyses indicated that opossums shifted microhabitat use toward eastern red cedar (Juniperus virginiana) forest when density of raccoons was reduced. Geographic Information Systems analyses at the habitat-patch scale revealed no differences in habitat selection after raccoon reduction. Niche breadths were high for both species, but niche overlap varied by time and treatment. Overlap of habitat patches between raccoons captured preremoval and opossums captured postremoval was high, suggesting a shift in habitat selection. The niche shift by opossums and change in niche overlap between raccoons and opossums supported our competition hypothesis. We acknowledge our lack of replication, but note that our work represents the 1st report of experimental manipulation coupled with work at multiple scales to examine competitive relationships between these key mesopredators.