This item contains the data for "Quality Upgrading and Technology Adoption in Agricultural Supply Chains: A Field Experiment in Vietnam”, which is the second chapter of "Essays on Relationships and Contracts". The chapter examines the impacts of technology training and buyer-supplier relationship on technology adoption and quality upgrading. We randomly varied subjects of each training group across farmer--exporter clusters—farmers, exporters, both, or none—and provided training on Good Agricultural Practices (GAP). And the dataset uploaded contains the data collected from the field experiment.