Farmers know much more than we think, and they are keen to improve their knowledge in order to improve their farms and increase their income. On the other hand, decision-makers, organizations, and researchers are increasing their use of citizen volunteers to strengthen their outcomes, enhance project implementation, and approach ecosystem sustainability. This paper assesses the role of citizen science relating to agricultural practices and covers citizen science literature on agriculture and farmers’ participation during the period 2007–2019. The literature was examined for the role of citizen science in supporting sustainable agriculture activities, pointing to opportunities, challenges, and recommendations. The study identified the following gaps: insufficient attention to (1) long-term capacity building and dialogue between academics and farming communities; (2) developing countries in the global South and smallholders; (3) agriculture trading and marketing; (4) the rationales of selecting target groups; (5) contributing to accelerated sustainability transitions. The main aim of the research projects reviewed in this study tended to focus on the research outcomes from an academic perspective, not sustainable solutions in practice or sustainability in general. More research is needed to address these gaps and to widen the benefits of citizen science in sustainable agricultural practices.