With the increasing retirement age, it is of critical importance to understand how teachers of different ages may stay engaged and how resources play a role in this regard. Although studies have linked job and personal resources to engagement (Xanthopoulou et al., 2007, 2009), we add to this literature by examining a moderated mediation model in which age moderates the impact of job resources on self-efficacy and optimism and consequently engagement over time. The results among 648 teachers showed a significant mediation effect of self-efficacy (b = .07, SE = .02, 95% bias corrected bootstrap CI: .03-.12) and optimism (b = .08, SE = .03, CI: .03-.15) on the relationship between job resources and engagement over the course of three weeks after controlling for the baseline measures. We found support for a moderated mediation effect in the sense that job resources had the strongest effect on self-efficacy (index of moderated mediation: .12, SE = .05, 95% CI: .05-.26) and on optimism (index of moderated mediation: .10, SE = .05, 95% CI: .02-.21) for older teachers. Although this group experiences lower levels of self-efficacy and optimism, they thus benefit more from job resources to stay engaged.