The family Micromomyidae includes diminutive plesiadapiforms characterized by highly specialized premolars and relatively primitive molars. Perhaps as a result of their small size, micromomyids show a spotty distribution through space and time, with documented records ranging from the middle Tiffanian of Alberta to the early Wasatchian of Wyoming. The micromomyids of Big Multi Quarry, an early Clarkforkian site in southwestern Wyoming that has yielded the most diverse plesiadapiform fauna known to date, are described here. Dryomomys dulcifer, new species, is the oldest and most primitive species of this rare micromomyid genus currently known. Tinimomys tribos, new species, retains primitive dental features that have been modified in Tinimomys graybulliensis Szalay, 1974. The apparent sympatry shown by Dryomomys and Tinimomys at Big Multi Quarry suggests that these closely related micromomyids occupied distinct ecological niches, although the nature of any such distinctions remains unknown.