<p>While existing literature suggests that environmental corporate social responsibility (CSR) is related to green customer loyalty (GCL), the mechanisms underlying this relationship have yet to be fully explored. This study examines the serial mediating effects of green reputation and green customer satisfaction (GCS) on the relationship between environmental CSR and GCL. Data were collected using a structured questionnaire from 294 customers in the solar photovoltaic (PV) supply chain in Tanzania. The data were analyzed using partial least squares structural equation modeling (PLS-SEM), and the findings reveal that environmental CSR is positively and significantly related to green reputation, GCS and GCL. In addition, green reputation is positively and significantly related to both GCS and GCL. Similarly, the relationship between GCS and GCL is positive and significant. Furthermore, green reputation and GCS partially mediate (individually and serially) the relationship between environmental CSR and GCL. Therefore, green reputation and GCS serve as key mechanisms through which environmental CSR positively influences GCL. This study extends the existing body of literature by shedding light on these mechanisms, i.e., green reputation and GCS through which environmental CSR relates to GCL, thereby confirming a serial mediation model. This study has some practical implications to the policymakers, customers and business managers within solar PV supply chains.</p>