Prior literature suggests that social media may increase older adults' well-being because they use social media to communicate with close social ties, such as family members. Despite this potential being recognized and associations between social media and well-being being established among older adults, the role of social media contact (SMC), particularly with family members, as a source of well-being has been little explored. In this study, we tested whether SMC with family members increases happiness for older (68–74 year-old) and younger and middle-aged (19–56 year-old) adults. Using population-based data from Finland, we examined the extent to which self-rated happiness is dependent on the respondents' sustenance of SMC with given family members. This analysis involved 2807 social media users. The family members examined were children and siblings for both generations; in addition, grandchildren for the older generation and parents for the younger generation. Propensity score matching was used to improve the credibility of the estimated associations. Partially supporting the socioemotional selectivity theory (SST), the results show that the older generation has more SMC with family members than the younger generations does; however, SMC with family members did not increase happiness among older adults, as SST suggests. Conversely, for younger adults, SMC with some family members was associated with increased happiness, suggesting that social media may gratify some family-related needs more specific to middle-aged adults than to older adults. This study adds to the knowledge about life-stage specific factors that contribute to subjective well-being in the digital era.