This 98-page master's thesis examines how productization impacts knowledge transfer in professional service firms' internationalization processes. The study focuses on a case company operating in debt administration services in Finland, Sweden, and Norway. Through a literature review and empirical case study, the thesis found that for professional service firms to efficiently utilize employees' tacit knowledge during internationalization, that knowledge must be shared organization-wide. By leveraging productization as a knowledge sharing mechanism, a professional services firm can apply and transfer knowledge more profoundly during international expansion than would otherwise be possible. Productization alone may not be sufficient, but complementing it with an open organizational culture and communication can help a professional services firm maximize the benefits of productization for knowledge transfer