ABSTRACT: BACKGROUND:Despite the high potential to improve the quality of life of patients and families, palliative care services face significant obstacles to their use. In countries with high-resource health systems, the nonfinancial and nonstructural obstacles to palliative care services are particularly prominent. These are the cognitive barriers -knowledge and communication barriers- to the use of palliative care. To date no systematic review has given the deserved attention to the cognitive barriers and facilitators to palliative care services utilization. This study aims to synthesize knowledge on cognitive barriers and facilitators to palliative care use in oncology and hemato-oncology from the experiences of health professionals, patients, and their families. METHODS:A systematic review was conducted. PubMed, PsycINFO, International Association for Hospice and Palliative Care/Cumulative Index of Nursing and Allied Health Literature (IAHPC/CINAHL), and Communication & Mass Media Complete (CMMC) were systematically searched for the main core concepts: palliative care, barriers, facilitators, perspectives, points of view, and related terms and synonyms. After screening of titles, abstracts, and full-texts, 52 studies were included in the qualitative thematic analysis. RESULTS:Four themes were identified: awareness of palliative care, collaboration and communication in palliative care-related settings, attitudes and beliefs towards palliative care, and emotions involved in disease pathways. The results showed that cognitive barriers and facilitators are involved in the educational, social, emotional, and cultural dimensions of palliative care provision and utilization. In particular, these barriers and facilitators exist both at the healthcare professional level (e.g. a barrier is lack of understanding of palliative care applicability, and a facilitator is strategic visibility of the palliative care team in patient floors and hospital-wide events) and at the patient and families level (e.g. a barrier is having misconceptions about palliative care, and a facilitator is patients' openness to their own needs). CONCLUSIONS:To optimize palliative care services utilization, awareness of palliative care, and healthcare professionals' communication and emotion management skills should be enhanced. Additionally, a cultural shift, concerning attitudes and beliefs towards palliative care, should be encouraged.