The Common Agricultural Policy 2014–2020, set up in 2015 and extended until 31 December 2022, introduced a payment instrument called Greening. The aim of Greening was to encourage agricultural practices that are beneficial for the environment while also contributing to economic and territorial dynamism. The purpose of this article is to study the effect that Greening has had in Spain. We consider five difference-in-difference models, one for each of the variables proposed: ecological focus areas, permanent grasslands over utilised agricultural area, CO2 emissions stemming from agricultural land use changes and the presence of woody crops, agricultural income, and affiliates of the special agricultural regime. The data used come from the Spanish Ministry of Agriculture, Fisheries, and Food, the Ministry for Inclusion, Social Security, and Migrations, and the Spanish Emissions Inventory System. For the diff-in diff estimations, we use Spain’s regions as control and treatment units from 2011 to 2018, the aim being to provide observations ex ante Greening (2011–2014) and ex post (2015–2018). The results show that Greening had a limited impact, questioning its efficiency for meeting its goal, and that it is not a sound precedent for building the new green architecture of the CAP.