Previous research has shown that social organization may affect the distribution of traditional ecological knowledge (TEK) within local communities of natural resource users in multiple ways. However, in this line of research the potential role of informal relationships has mostly been overlooked. In this article, we contribute toward filling this research gap by studying how two types of informal relationships, namely migration partnership and friendship, affect the distribution of TEK within a community of seminomadic pastoralists from the Kutch area, Gujarat, India. Using social network analysis, we map three networks, migration, men friendship, and women friendship, and compare with similarity-based quantitative approaches the clusters extracted from these networks in relation to four domains of TEK: knowledge about soils, about ethnoveterinary practices, about sheep breeds, and in ethnobotany. Our results show that (1) migration clusters are associated to significant variations in three TEK domains, while (2) friendship clusters are associated to minor variations. We relate these results to the importance of common practical experiences involved by joint migration. Moreover, kin relations are shown to strongly underlie friendship and migration relations, and as such appear as a potential driver of the dynamics of the local TEK system. We conclude by advocating for a better inclusion of such informal relationships in future research on local TEK dynamics, following recent developments in studies on natural resource governance. ; This research was conducted within the CONSOLIDER SimulPast project (>Simulating the Past to Understand Human Behaviour,> CSD2010-00034), funded by the former Spanish Ministry for Science and Innovation. We thank all inhabitants of Mindiyala and Kutch who helped us and the Marag nongovernmental organization for contact facilitation. ; Peer Reviewed