Facing constant cyberattacks, organizations should use IT security tools, train employees, and motivate them to comply with security policies. Accordingly, employees’ extra-role security behaviors can benefit organizations as an additional line of defense. Drawing on organizational climate theory, we examined the psychological mechanisms through which organizational security climate could shape extra-role security behaviors. These mechanisms, such as employees' increased organizational security concern and a broader definition of their perceived security-related responsibilities, were found to have a full mediating effect between organizational security climate and extra-role security behaviors. This research contributes to the information security literature by presenting an empirically validated model that provides nuanced insights into the role of organizational climate in shaping extra-role security behaviors.