Using educational advisors to facilitate the implementation of innovations in schools is a widespread, yet still relatively little studied and understood strategy in reform policies. This article reports on an exploratory, multiple case study on the support provided by external advisors to secondary schools in Flanders (Belgium) on the implementation of a new policy on inclusive education. We found that the form and content of support practices were constituted and determined by four thematic elements: congruency, legitimacy, loyalty, and urgency. Striving for congruency between the agendas of several parties appeared to be an important theme in the interpretations, negotiations, and appreciation of support practices. Furthermore, support practices were found to be constituted by the advisors' loyalty towards the organisations they worked with. The acquisition of legitimacy as an advisor, necessary for receiving a clear mandate from the school teams, was a third factor. A final key factor in external support practices was the sense of urgency around the agenda of the external support, felt by members of the school team.