This present study examines how work overload affects cybersecurity behavior, considering job stress as a mediator and corporate ethics as a moderator. Using a time-lagged survey design, 377 South Korean employees were surveyed. The results of SEM analysis (structural equation model) show that work overload leads to higher job stress, which in turn worsens cybersecurity behavior. High levels of corporate ethics buffer this negative relationship. This research fill gaps in the existing literature by linking work overload, job stress, and corporate ethics to cybersecurity behavior, offering valuable insights for both theory and practice. Future research directions are also discussed.