<p>Human society is characterized by an interest in understanding the world and its phenomena. However, for most of society, science is a distant endeavor, reserved for a select group, and a wide gap exists between scientists and citizens. This gap is even more striking in psychology, where humans are the study subjects of interest. Citizen science (CS) is a recent approach that incorporates perspectives of nonprofessional scientists or “citizens” through their active participation in scientific research. Because CS remains largely unexplored within several subdomains of psychology, including cognitive psychology, this review highlights the opportunities that CS can offer for our field. After situating the relation between science and society and the emergence of CS in the history of science, we provide an overview of existing definitions and models of CS, which we then synthesize into a new model. We also describe CS studies within the field of psychology, with a specific focus on cognitive psychology. Crucially, we discuss the main opportunities and challenges of CS, zooming in on specific challenges that CS faces within psychology and cognitive psychology in particular. Ultimately, this review aims to bridge the gap between psychologists and their study subjects, by stimulating the development and application of a citizen science approach within cognitive psychology.</p>