Purpose The purpose of this paper is to develop and analyze a model of factors influencing interpersonal conflicts. Design/methodology/approach This research was conducted using a mixed method approach. In the qualitative study, the conceptual model of the factors affecting interpersonal conflicts was extracted from semi-structured interviews with 17 relevant experts using a theme analysis technique. Then, three hypotheses were developed based on the model and relevant theoretical evidence. Using a researcher-made questionnaire which was developed earlier based on the qualitative results, a quantitative-based survey was performed to assess the interpersonal conflicts and also the standard scale of the level of interpersonal conflicts (Jehn, 1997). The hypotheses were tested on a sample of 160 employees of Chaharmahal and Bakhtiari Province Gas Company (CBPGC). Findings The results of the qualitative study indicated that individual factors including personality dimensions and individual differences; organizational factors including five dimensions of organizational culture, organizational structure, management characteristics, intra-organization factors and human resource systems; and environmental factors influenced the creation of interpersonal conflicts. The results of the quantitative study indicated that organizational factors with an effect size of 0.502 were identified as the most important factor influencing interpersonal conflicts. Research limitations/implications The findings of this study can provide a roadmap to managers of the CBPGC to be aware of the contributing factors to conflict within their organization. Originality/value The use of mixed method to identify the causes and factors of interpersonal conflict and analyzing a context different from previous studies can be considered as the innovations of this study.