This paper aims to discuss the challenges in the process of building a learning community in Vietnamese primary schools. Five lessons emerge from the cases. First, changing teachers' beliefs is time-consuming. Second, because of the reluctance of teachers to change, large-scale delivery of the educational project should be critically revisited with regard to its effectiveness. Third, learning community requires the building of trust among actors, including external resource persons. Fourth, external resource persons should continue learning sincerely to gain teachers' trust. Fifth, the concept of sustainability should be revisited as something that is never-ending and that cannot reach perfection.