Although extensive literature has contemplated apathy in Alzheimer s Disease (AD), most studies assessed this concept as a unidimensional construct. This systematic review explores the behavioural, cognitive, and affective dimensions of apathy in AD. We performed a systematic analysis of original cross-sectional studies, using specific search terms for each apathy dimension on the PubMed database. After meeting the eligibility criteria and being assessed for quality, a total of 17 studies were reviewed. The results suggest that the behavioural dimension of apathy is the most prevalent in AD, negatively affecting decisionmaking processes and being correlated to reduced grey matter volume in the frontal pole and hypoperfusion in the right anterior cingulate cortex. Cognitive apathy is related to executive dysfunction and disruptions in the dorsolateral-prefrontal circuit. Affective apathy is less prevalent, being associated with reduced theory of mind, higher levels of physical agitation, alterations in the left superior frontal gyrus and reduced grey matter volume in the left insula. Patients with AD present reduced awareness of apathetic symptoms for all dimensions. These findings emphasise the different presentations and neural correlates of the dimensions of apathy among AD patients. Exploring these distinct apathy patterns leads to the possibility of personalised care for AD patients, also opening new perspectives of therapeutic interventions for apathy in AD.