This study contributes to the emerging literature on age diversity effects at the organizational level of analysis by comparing the role of chronological-age diversity versus subjective-age diversity. We hypothesize a multilevel model in which organizationallevel subjective-age diversity is negatively related to bonding social capital within organizations, which, in turn, contributes to heightened employee engagement and lowered turnover intentions. The assumed relationships are tested in a multilevel sample of 96 German small- and medium-sized companies with 16,274 employees participating. We gathered data from four different sources to circumvent common source problems and received support for most of the proposed relationships. Given the potentially detrimental effects of high subjective-age diversity in the workplace, the paper concludes with practical recommendations on how to manage subjectiveage diversity in companies proactively.