In this study, I apply the concept of entitativity (perceptions of "groupness") to demographically diverse workgroups. I propose that group-level entitativity will interact with group gender and ethnic diversity; the negative relationship between diversity and group outcomes will weaken at high levels of group entitativity. I use multi-level modeling to test these hypotheses using field data from small work groups. The results suggest that group entitativity does interact with gender diversity in the expected direction. Gender diverse groups with higher entitativity had more satisfied members. Results for ethnically diverse groups did not unfold in the expected direction. Further, group member identification was not influenced by diversity, nor did this relationship change with group entitativity ratings. Supplemental, group-level analyses shed some light on the hypothesized relationships. I discuss theoretical implications for applying entitativity to the study of demographically diverse work groups.