We provide evidence on the role of spillovers through vertical linkages in service firms' internationalisation process. We combine input-output coefficients with region-level information on downstream manufacturing sector exports to build a measure of spillovers through backward linkages, which we assess as a systematic determinant of Italian BS firms' export status. Once considered firm and sector specificities, export spillovers especially matter for exporting to high-income economies outside Europe. This finding originates from higher sunk costs stemming from greater distance to the destination market and tougher competition within the destination market. Furthermore, the spillovers' geographical scope is mainly local. We thus contribute to international business theory by generalising existing evidence from case studies on the importance of buyer-supplier relationships for service firms' internationalisation across several BS sectors. Our research carries important implications for international business practices as well, as joining networks with internationalised customers may play an important role in enhancing BS firms' exports, regardless of the BS supplied. © 2013 Elsevier Ltd