The flourishing trend of using multiple technology-based self-service channels (hereafter, SSCs) can be found across various service industries. So far, no studies have explored the effect of multichannel interaction on breadth consumer relationship breadth (i.e., cross-buying intention). Based on brand extension theory and the cross-buying literature, this study proposed a conceptual model for understanding the key determinants of consumer cross-buying intention in the context of multiple SSCs. A total of 262 respondents who had experience with using both online and mobile banking were collected. The result revealed that perceived online banking quality (i.e., original SSC), image congruity, and value congruity facilitate consumer trust and satisfaction toward a mobile banking service (i.e., extension SSC). In addition, the trust and satisfaction toward mobile banking have a positive influence on crossbuying intention. The result of this study not only provides an academic contribution to the multichannel service and SSC literature but also provides suggestions for service providers who wish to develop their multiple-SSC strategies.