This study examined how, from the family business advisor’s perspective, knowledge sharing among external individual advisors can affect the quality of services provided to the family business client. Using qualitative research methods, we found that knowledge sharing improved the quality of advising services through four mechanisms: (a) by improving the accuracy of issue identification, (b) by achieving a systematic analysis of the issue, (c) by arriving at an integrated total solution, and (d) by increasing the credibility of the provided solution. This study has important implications for literature in the field of family business advising, as it explains the underlying mechanisms through which knowledge sharing among individual external advisors enhances the quality of advising services.