Concern over the effect of industries on the natural environment is growing on a multitude of levels. This study examines the effects of how perceptions of (a) environmental values, (b) green image and (c) perceived value of industrial customers influence their loyalty towards suppliers in existing relationships, and how the length of B2B relationships may moderate these linkages. A conceptual framework is developed and data are collected from a global sample (N =121) of B2B customers. We find that both green image and perceived value have a direct positive link with customer loyalty and that environmental values are positively linked to the green image of the supplier. Moreover, the effect of green image on loyalty is mediated by perceived value, with environmental values only indirectly linked with perceived value of the supplier. As the length of relationship increases, on one hand the positive relationship between green image and customer loyalty is strengthened, while on the other the positive relationship between environmental value and green image is weakened. Regardless of how environmentally aware the customer is, green image is a strong predictor of both perceived value and loyalty. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment