Using data from 2015 to 2018 waves of the Longitudinal Study of Older Adults in Anhui Province, China, this study investigated associations between different forms of social disconnectedness (social isolation, loneliness, living alone) and psychological well-being of older adults longitudinally. The results showed that social isolation and loneliness were independently associated with psychological well-being, whereas living alone was not. Different forms of social disconnectedness had additive and interactive effects on psychological well-being of older adults. Those who were exposed to all three forms of social disconnectedness suffered from the lowest level of psychological well-being. Moreover, the adverse effects of social disconnectedness on psychological well-being were found to be stronger for older women than for older men. The results underscore the necessity to consider multiple forms of social disconnectedness as well as their different combinations in explaining psychological well-being in later life.