Introduction: Factors such as prolonged sitting at work or improper posture of head during work may have a great role in neck pain occurrence among office employees, particularly among those who work with computers. Although some studies claim a significant difference in head posture between patients and pain-free participants, in literature the forward head posture (FHP) has not always been associated with neck pain. Since head, cervical and thoracic postures and their relation with neck pain has not been studied in Iranian office employees, the purpose of this study was to investigate the relationship between some work-related and individual factors, such as poor posture, with neck pain in the office employees. Material and methods: It was a cross-sectional correlation study carried out to explore the relationship between neck pain and sagittal postures of cervical and thoracic spine among office employees in forward looking position and also in a working position. Forty-six subjects without neck pain and 55 with neck pain were examined using a photographic method. Thoracic and cervical postures were measured using the high thoracic (HT) and craniovertebral (CV) angles, respectively. Results: High thoracic and CV angles were positively correlated with the presence of neck pain only in working position (p < 0.05). In forward looking position, there was no statistically significant difference between the 2 groups (p > 0.05). Conclusions: Our findings have revealed that office employees had a defective posture while working and that the improper posture was more severe in the office employees who suffered from the neck pain.