We leverage conservation of resources (COR) theory to explain how conscientiousness and emotional stability (ES) are associated with resource management strategies that may reflect instrumentally driven counterproductive work behaviour (CWB). Specifically, we investigated how the relationship between conscientiousness and CWB varies as a function of the level of available personal (i.e., ES) and organizationally provided (i.e., experienced job constraints) resources. Results from two surveys administered 4 weeks apart to US employees indicate that the negative relationship between conscientiousness and CWB is positive among employees who are low in ES.