This chapter offers a comprehensive integration of philosophical and psychological perspectives on gratitude, tracing their historical development from classical thinkers such as Cicero and Seneca to moral sentimentalism and theories of emotion, as well as more contemporary approaches. Considerations from deontological approaches and theories of emotion intersect with the analysis to synthesise central themes in theories of triadic gratitude. This analysis also highlights the need for further conceptual development of dyadic gratitude across both philosophical and psychological domains.