The central objective of the present study was to investigate whether it would be possible to facilitate increases in openness to new experiences in later adulthood. Specifically, we investigated whether individuals with higher internal control beliefs (personal resource) provided with training to successfully prepare them for a challenging volunteering context (contextual resources) would increase in openness. Participants of the training program (n = 148, 44-72 years, M_age = 62.80) and a control group of volunteers (n = 92, 46-80 years, M_age = 63.01) were assessed 3 times: before the training program (T0), after the training program (T1), and 1 year later (T2). As expected, there was a significant training by internal control beliefs interaction such that participants of the training program with higher internal control beliefs increased significantly in openness relative to control participants between T1 and T2. The current study provides evidence for the plasticity of personality in later adulthood and confirms the importance of both personal and contextual resources.