In this article, we propose that age similarity preference (ASP) among employees increases workplace difficulties in an age-diverse environment. Individuals use social categorizations such as age groupings to help minimize uncertainty, cope with change, and deal with complexity. When placed in an age-diverse work environment, intergroup comparisons regarding age become more salient. We suggest that when a preference exists among employees to work and interact with those similar in age to themselves in an age-diverse workplace, this will lead to an increase in uncertainty, perceived workplace challenges, and subsequently conflict. Data were collected from 262 employees of an organization in the US Midwest to test our hypotheses. Using multiple mediation modeling, our results suggest that ASP influences the degree of conflict reported, and that uncertainty and perceived work-related challenges mediate the relationship between ASP and conflict. A post-hoc ANOVA analysis of our data also showed a significant relationship between employee age and ASP, indicating that this preference was more likely to be reported by individuals younger in age.