Access to mental health care service remains a major problem globally, but more obvious in developing countries including the Gambia. In general, mental illnesses even though are acknowledged as great contributors to the global burden of disease, they receive little attention at global, regional and local levels compared to other illnesses such as communicable diseases. Access to mental health care in the Gambia deserves urgent attention. Whereas no recent study is done to examine the prevalent rate and treatment gap, the available data shows that 90% of mentally ill patients who require treatment do not receive it. The aim of this study was to contribute to the improvement of access to mental health care service by exploring factors that influence access to mental health care service in the Gambia using a qualitative research design. In-depth interviews with 15 mentally ill patients using the community mental health services and 5 focus group discussions with the general population in the same health region were conducted. The findings of this study highlight many factors that could influence access to mental health care service among people with mental illness in the Gambia. The most important of these factors that shed light on access to mental health care service include; perception of and believed causes of mental illness, the scarcity of biomedical service for most of the population, resulting in patients and their families using what is available and long distance to access services. The lack of satisfaction from these services also leads to syncretic use of different treatment systems, coupled with high cost of treatment (traditional system) and antipsychotic medicine. The findings further show that the patient’s family shoulder the responsibility of providing the required financial resources for treatment and medication, but also decide where treatment is sort from. Efforts to improve access to mental health services should be approached holistically, as it is influenced by social, family and health system factors. This study however provides a base for action to address access to mental health care service. Collaboration with traditional healers, provision of mental health services through the community mental health team and long term plan to address poverty can improve access to mental health service in Gambia.