Health promotion is a top priority worldwide. This includes mental health in older adults, who are at risk due to the ageing process, associated with deteriorating health status. Notwithstanding the importance of the topic, psycho-social factors are often neglected in the implementation or formulation of advanced age health promotion programs. In this context, it is imperative to reach a better understanding of the main psycho-social aspects involved in mental health promotion in older adults. The main objective of this narrative review was to identify documents that made a core contribution to the understanding of psycho-social factors related to mental health in community-dwelling older adults. To achieve this, a narrative review was carried out that included a total of 40 articles published between 2018 and 2022. This review was performed through an interpretive stance. Ethical approval was not required for this review. Three main categories were derived from thematic analysis: (i) mental health interventions; (ii) mental health and frailty in older adults, and (iii) social support in older adults. To conclude, understanding the main protective psycho-social factors involved in mental health in community-dwelling older adults is of paramount importance. Identifying the implications of the psycho-social factors in this population is vital to elaborate specific interventions, therefore enhancing their mental health.