This paper provides a comparative analysis of the social and cultural dimensions of fish hatchery development in Vietnam and Thailand. Two detailed case studies highlight the importance of a variety of culturally mediated, informal interpersonal relationships in facilitating the establishment of new hatchery enterprises. The analysis reveals that in both Vietnam and Thailand, informal relationships are extremely effective conduits for the transfer of productive technologies from public institutions to private entrepreneurs and for the subsequent development of private enterprises. It is concluded that if current policies aimed at promoting private sector development are to be more successful, they must be better tailored to the contours of specific cultural geographies in locations where they are implemented.