This paper explores critical success factors (CSFs) in the transfer of after-sales information technology (IT) support knowledge from IT product and service firms that provide IT support services (“IT support organisations”) to enterprise customers, when Web-based Self-service Systems (WSSs) are used. The research explores the topic from an IT support organisation perspective in an interpretive multi-stage study involving six large multinational IT support businesses. Key findings reported in the paper include six categories of CSFs, and twenty-seven CSFs distributed across the six categories.  The findings suggest that researchers and practitioners consider planning and implementing WSSs for after-sales IT support provision within a complex network of IT support organisations, business partners and enterprise customers.