Markets for agroecological food and inputs are actively shaping ecological forms of agriculture. The processes that set up these two sets of markets, both upstream and downstream of farms, have an impact on agricultural systems and practices. To defend this thesis, we introduce results from ongoing studies over the past fifteen years of different forms of agroecology in France, Argentina, and Brazil. Without intending to be exhaustive, our examples focus on the effects of certification systems, marketing infrastructures, and companies’ strategies. The article also demonstrates the role of the State in the political construction of these markets and, therefore, in the shaping of agroecologies.