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Extensive Wyoming big Sagebrush (Artemisia tridentata ssp. wyomingensis) rangelands of the Great Basin have been mowed for fuels management. Shrub mowing can promote healthy Wyoming big sagebrush plant communities that are more resilient, less flammable and less likely to transition to a state dominated by exotics following wildfire.  Or, mowing can favor exotic vegetation.  Given these divergent potential effects, managers need enhanced capabilities for predicting mowing outcomes.  We tested hypotheses across northern and central Nevada by analyzing soil surface and vegetation cover data from 76 unmowed and adjacent strips mowed between 2001 and 2010.  Mowing increased litter, basal live vegetation cover, and foliar cover of perennial grasses, herbaceous exotics, cheatgrass, and exotic forbs.  It decreased cover of sagebrush, cryptogams, and bare soil. Response of native grass correlated with native grass, cheatgrass, and native and exotic forbs in paired unmowed areas. Native herb dominance in mowed areas increased with up to 15-20% native grass cover.  Mowing increased herbaceous cover of native perennials more than exotic annuals where unmowed exotics were not dominant or subdominant. Foliar, absolute, and relative cover of mowed cheatgrass and exotic forbs inversely correlated (p<0.01) with unmowed sagebrush relative cover. Cover shifts (from control to mowed) of bare soil, rocks, native graminoids, all graminoids, and other shrubs correlated with unmowed sagebrush cover and relative cover.  Low native grass cover appears to increase risk of post-mowing exotics domination, especially where cheatgrass was greater than about 10%. Mowed cheatgrass cover correlated with both native and exotic forbs in unmowed areas. The best herbaceous cover variables for predicting herbaceous responses following mowing are native grass and cheatgrass.  Locations most likely to respond positively have herbaceous vegetation dominated by perennial grasses, have little cover of cheatgrass or other annuals, and are dominated by sagebrush, especially if it is not too large.