In this paper we analyze the relationship between hot topics in economic development such as global knowledge pipelines (GKP), tacit knowledge (TK) and social capital (SC). In particular, echoing the work of Gertler (2003) and Bathelt et al. (2004) we stress that GKPs are important not only as conveyors of codified knowledge, but also of TK. In this paper, we make two additional operations; the first is extending the concept of TK to include systematically the concept of SC. Traditionally, TK tends to be conceived as individual experiential knowledge based on practice, in a way part of the human capital embodied in the highly-skilled individual expert. We’d rather include here also collective pools of social knowledge otherwise called SC since TK can be created and later transferred by wider communities. In this operation we benefit from Blacklers (2002) typology of knowledge that appropriately includes aspects of localized SC in the form of ‘encultured’ and ‘embedded knowledge’. In the second operation we extend Williams argument (2007) on the richness of migrants’ codified and tacit knowledge; in fact, we assert that TK flows do not rely only upon highly knowledgeable economic agents such as scientists, engineers and top managers, but on a broader spectrum of individual and collective agents that are and/or can be part of competitive GVC/GPN/GKP. This discussion has special importance for local production systems (LPS) such as clusters and districts, where TK flows and SC are transforming dramatically, thus need more thorough theoretical frameworks to represent these changing socioeconomic scenarios, as well as their real constraints and opportunities.