This paper presents a new model of gratitude incorporating not only the gratitude that arises following help from others but also a habitual focusing on and appreciating the positive aspects of life", incorporating not only the gratitude that arises following help from others, but also a habitual focusing on and appreciating the positive aspects of life. Research into individual differences in gratitude and well-being is reviewed, including gratitude and psychopathology, personality, relationships, health, subjective and eudemonic well-being, and humanistically orientated functioning. Gratitude is strongly related to well-being, however defined, and this link may be unique and causal. Interventions to clinically increase gratitude are critically reviewed, and concluded to be promising, although the positive psychology literature may have neglected current limitations, and a distinct research strategy is suggested. Finally, mechanisms whereby gratitude may relate to well-being are discussed, including schematic biases, coping, positive affect, and broaden-and-build principles. Gratitude is relevant to clinical psychology due to (a) strong explanatory power in understanding well-being, and (b) the potential of improving well-being through fostering gratitude with simple exercises. Copyright © 2010 Elsevier Ltd. All rights reserved.