||In India, there is increasing recognition among policy-makers of the largely untapped potential of the Eastern Indo-Gangetic Plains (IGP) for meeting state- and national-level food needs. Zero-tillage (ZT) is a proven technology for enhancing wheat productivity and, hence, food security in the IGP, while reducing production costs – a ‘win-win’ scenario that should support rapid technology scaling even though adoption remains modest to date. In order to inform policies and derive recommendations for a more effective extension strategy, this study investigated determinants of ZT adoption in the Eastern IGP using a random sample of 1000 wheat-growing households from Bihar, stratified by ZT adoption status. We corrected for potential non-exposure bias by using a two-stage estimation procedure that differentiates between factors affecting farmers’ awareness of ZT and those affecting adoption conditional on awareness. Owing to the relatively nascent stage of ZT diffusion in the area, we emphasized the role of information in the adoption process, including social networks, whereby we allowed for endogenous and exogenous network effects. Only 44% of sample households knew about ZT technology, and there was substantial scale bias in favor of larger scale farmers both with respect to awareness and adoption. Both the adoption behavior and characteristics of the respondents’ network members influenced their own awareness and adoption of ZT, particularly among farmers in the smallest landholding tercile. Farmers valued the time-saving potential of ZT, especially under conditions of increasingly unreliable monsoon rains resulting in a delayed rice crop and, consequently, late establishment of wheat which reduces yield. The fact that most farmers accessed ZT via custom-hire services was accounted for in the model, and the importance of proximate service providers confirmed. We conclude that there is need for further awareness-raising campaigns for ZT technology, whereby, apart from mass media, agricultural extension should use contact farmers belonging to different social strata for effective within-village diffusion of messages, especially to the poorer farmers. The social inclusiveness of ZT use can be enhanced by supporting the emergence of more ZT service providers and by developing business models that lower the transaction costs of servicing smaller farms.