Objective: The exposure to negative acts at work is one of the main issues highlighted adverse health effects within the scope of work life's psychosocial dimension. Mobbing is defined as both the most common one among the causes of stress being at work, and also more devastating and damaging than the other stressors of the work. The aim of the present study was to examine the reliability of the Turkish version of the Negative Act Questionnaire (NAQ-TR). Methods: The questionnaire was first translated into Turkish and then back translated into English and the equivalence of both versions was determined. An expert group analyzed the formulation of the translated items and they redrafted some of them according to agreedon criteria. Subsequently, it was administered to 456 workers from 11 different workplaces. The factor structure and internal consistency of the NAQ-TR was examined. Result: The instrument showed satisfactory internal consistency with an overall Cronbach a of 0.912. The factor analysis, as opposed to the original scale, yielded four factor solution (Personal bullying and isolation, Work-related bullying, destabilization and excessive workload). We found that NAQ-TR has high internal consistency. Conclusions: The Turkish version of NAQ was found to be reliable for mobbing in workplace. It can be used in epidemylogic trials.