The purpose of the study is to develop and test an analytical model for resilience assessment of supply chain risks against the risks of system and its individual tiers. In this regard a multi-method research approach is adopted as follows: By using data envelopment analysis (DEA) and fuzzy set theory, a fuzzy network DEA model has been proposed to assess risk in overall supply chains and their individual tiers. The proposed model is tested by surveying of 130 people as selective petrochemical companies in Iran. The survey results show a substantial variation in resilience ratings between the overall petrochemical supply chains and their individual tiers. The research findings indicate that system resilience is not necessarily indicative of the resilience of its individual tiers. On the other hand, high efficiency scores in supply chain tiers have limited influence on overall resilience of supply chain. The proposed analytical model enables the assessment of supply chain flexibility at different levels for a wide range of supply chain risks in upstream, downstream and downstream process-es.