There is now a growing body of research demonstrating the physical health benefits of being grateful. However, research has only just began to explore the mechanisms accounting for this gratitude-health relationship. This study examines the relationship between dispositional gratitude and self-reported physical health symptoms, and explores whether this relationship is explained through reduced levels of perceived loneliness and stress. This study employed a cross-sectional design with a sample of 607 healthy adults. Serial mediation analysis revealed that the positive effect of gratitude on physical health was significantly mediated by lower reported levels of perceived loneliness and stress. These findings are important given evidence that gratitude can be cultivated, and may serve to buffer against stress and loneliness and improve somatic health symptoms in the general population.