Today, adult individuals must be able to continuously learn and adapt to the rapid changes occurring in society. However, little is known about the individual characteristics, particularly personality traits, that make adults more likely to engage in learning activities. Moreover, few studies have longitudinally and objectively investigated the influence of personality on engagement in lifelong learning throughout working age. This study therefore used longitudinal data (15 years) to examine which personality traits predicted level and long-term changes in learning activities among 1329 Swedish adults aged 30–60. The results from growth curve modelling showed that over the follow-up period, novelty seeking and self-transcendence were both positively related to overall level of engagement in learning activities, although not to rate of change. Regarding specific activities, novelty seeking was related to higher levels of engagement in attending courses, taking on new education, and making occupational changes, while harm avoidance was negatively related to the likelihood of changing occupation. The results of this study underscore the importance of considering personality in relation to engagement in lifelong learning activities. Insights from this study can potentially increase the likelihood of finding methods to promote lifelong learning, which can be beneficial for educators, policymakers, and companies.