The Agricultural Knowledge and Innovation System (AKIS) and the Farm Advisory Service (FAS) are important elements of the current Programming Period of the Common Agricultural Policy (2023–2027), as it is now deemed necessary to transition the European agricultural model to more sustainable forms, through the dissemination of agricultural knowledge, while simultaneously promoting innovative methods. An Agricultural Knowledge and Innovation System must be able to propose and develop ideas for the transmission of agricultural knowledge, promoting innovation and the exchange of ideas. The present study includes a significant number of investigations on the effectiveness of the implementation of the AKIS and the FAS so that the conclusions are representative of the scope of the work. The object in question is now the cornerstone of the modernization of agricultural production and an important way out towards more competitive models of agriculture. The purpose of this paper is to give an extensive overview of the degree of implementation of Agricultural Knowledge and Innovation Systems in the countries of the European Union (including the United Kingdom until 2019) from 2014 until today, essentially during the implementation of the second period of Common Agricultural Policy. In the context of this article, the main results of the research carried out in the EU countries during the period under study and the proposed improvements by the researchers, where they are mentioned, are recorded epigrammatically. Finally, the countries are categorized according to the degree of implementation of the AKIS and the contribution of the Agricultural Advisory System to more sustainable forms of agricultural practices.