Les mutations et la libéralisation des marchés agricoles et alimentaires mondiaux ont accéléré la formation de relations verticales entre producteurs et firmes agro-industrielles et la diffusion de l’agriculture dite contractuelle dans les secteurs de la production et de la commercialisation des produits agricoles. L'agriculture contractuelle est un accord entre un exploitant agricole et un acheteur (ou entreprise), établi avant la saison de production, pour une quantité et une qualité spécifiques du produit, avec sa datede livraison à un prix parfois préétabli. Le contrat garantit au producteur la vente assurée de sa production et une assistance technique et financière (crédit, technologie,intrants agricoles). L'acheteur quant à lui, a la garantie d'une offre régulière du produit et du contrôle de la qualité.Cette thèse vise à évaluer le rôle de l'agriculture contractuelle dans la durabilité des chaînes de valeur du riz au Vietnam.Dans la sphère sociale de la durabilité, nous avons démontré que les modèles d’agriculture contractuelle privilégient davantage les moyennes ou grandes exploitations agricoles du fait des coûts de transaction accompagnant le contrat et le volume de production désiré. Cela engendre l’exclusion des petits agriculteurs qui ont de faibles capacités de production. Toutefois, la participation à un système d'intégration horizontale permet de lever cette contrainte. Sur le plan économique, les producteurs sous contrat gagnent plus que les producteurs sans contrat (environ 121 USD/hectare). Finalement, sur le plan environnemental, les producteurs sous contrat sont disposés à adopter des pratiques respectueuses de l'environnement. Cependant, les coûts élevés des certifications environnementales découragent les firmes à inclure ces normes environnementales dans les attributs de contrat. / In recent years, the structure of the Vietnamese rice sector has changed. From a highly fragmented value chain producing rice for low value-added markets, the shift toward more vertically integrated and coordinated value chains through contract farming has begun to emerge. Contract farming is used as a tool to govern more effectively rice quality and penetrate new and lucrative markets for higher quality rice.Many empirical studies have assessed the role of contract farming in developing economies. Contract farming is perceived as an engine for rural development and a golden opportunity for farmers to have direct access to modern markets, agricultural inputs, credit, and technical support. Worldwide, contract farming adoption is promoted as an institutional innovation. In the Vietnamese rice sector, there is a specific legislation to encourage its diffusion such as the Small Farm Large Field program.This thesis aims at assessing the contribution of contract farming to internalize sustainable production standards in rice value chains. The central assumption of this thesis is that some contract attributes may contribute to improving sustainability. A set of attributes of performance declined in sustainable indicators was selected to test our research hypothesis. The attributes of performance stem from the Sustainable Rice Platform’s principles of sustainable rice production and the existing contract attributes in the Mekong River Delta.In the economic dimension of sustainability, we found that participation in contract farming improves the welfare of rice farmers as farmers selling their paddy using a contract gain, on average, $121 per hectare of paddy more compared to farmers producing outside of a contract. The increase in price is mainly a result of an increase in the selling price (price premium).In the social principle of sustainability, we found that participation in contract farming could improve the welfare of small rice farmers through rent and risk-sharing. Export firms share some of its profits with farmers through a price premium. However, due to the large heterogeneity of contract farming models in the Vietnamese rice sector, not all contract models facilitate risk-sharing. In a marketing contract, farmers bear all the production risks whereas in resource contracts some of the production risks may shift to the export firms. Therefore, resource contracts are more likely to improve equity through risk-sharing between farmers and export firms. Moreover, participation in resource contracts is found to improve farmers’ financial inclusion. Export firms are willing to prefinance farmers under contract. However, the opportunity cost of prefinancing may include the loss of farmers’ autonomy. Evidence from our discrete choice experiment reveals a conflicting interest between farmers and export firms regarding the decision rights in a contract. Last but not least, smallest farmers were excluded from contract farming as firms did not always want to support the transaction costs of dealing with numerous individual farmers. However, our findings suggest that the scale-bias could be successfully relaxed through the Small Farm Large Field program.Finally, in the environmental dimension of sustainability, we examined both firms’ and farmers’ prospective responses to the internalization of sustainability through contract farming using an experimental approach. Farmers are found willing to internalize the environmental dimension of sustainability through contract farming in exchange for a price premium. Export firms are found less likely to implement the GlobalG.A.P./VietGAP or the Pesticide free production standards. The cost of such standard implementation and the lack of institutional support are more likely to justify this outcome.