Objectives: This study investigated the relationship between informal lifelong learning (ILL) and subjective wellbeing (SWB) among Chinese older adults, focusing on potential psychosocial mechanisms. Method: Using 2017 China General Social Survey data, SPSS and PROCESS were applied to analyze relationships between ILL, hope, social class identity (SCI), and SWB. Hope was tested as a mediator, and SCIs (past, current, and change over time) were tested as moderators. Results: SWB positively correlated with ILL (0.284), hope (0.474), early-life SCI (0.194), current SCI (0.368), and SCI change (0.186). Hope partially mediated the relationship between ILL and SWB (indirect effect = 0.316, 95% confidence interval [CI]: 0.012–0.646). Current SCI moderated ILL–SWB (co efficient = 0.466, p < .01) and hope-SWB (coefficient = −0.064, p < .01) relationships, while SCI change moderated hope-SWB (coefficient = −0.058, p < .05). Conclusion: Older adults with lower current SCI or downward SCI mobility experience face inequities in accessing benefits related to ILL. Strategies such as “Nannagogy” and life-reviews are recommended to ameliorate these inequities.