PurposeThe purpose of this paper is to understand communication pathways and factors that cause sustainability initiatives to become contagious from downstream to upstream members of a supply chain, which is termed sustainable supply chain contagion (SSCC).Design/methodology/approachThis study takes an inductive, grounded theory approach, while utilizing established theories.FindingsThe decision to implement a sustainability initiative depends on the business case for the organization. Importantly, the findings outline several network and communication factors that overcome the weak business case and, therefore, foster SSCC. Based on these findings, a communication network model of SSCC is outlined. Network factors include the contagion pathways, the role of sustainability and top management teams and communication channels. Communication factors include the alignment of sustainability initiatives with departmental objectives, the articulation of goals and assuring the endurance of a sustainability initiative.Practical implicationsManagers can utilize the proposed model to create conditions that strengthen the business case of a proposed sustainability initiative, thus fostering SSCC. The presented findings reveal different tactics that can assist organizations in communicating sustainability initiatives in a persuasive manner, to permit the proliferation of sustainability across the supply chain.Originality/valueThis research enables a multilevel examination of the factors influencing SSCC.