The study investigated the socio-cultural factors influencing adherence to antiretroviral drugs among people living with HIV in a University Teaching Hospital in Southwestern Nigeria. It investigated the influence of various socio-cultural factors on adherence of PLWHA to treatment regimen People Living with HIV/AIDS (PLWHA) of antiretroviral therapy (ART) in Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife and assessed the prevalence of adherence to ART among PLWHA in the study area. These were with the view to ascertaining the influence of socio-cultural factors in the PLWHA's adherence to antiretroviral therapy in the study location. The study design was a cross-sectional where both qualitative and quantitative research methods were adopted. The quantitative data were collected using structured questionnaire. The participants were HIV diagnosed patients attending clinic at the Obafemi Awolowo University Teaching Hospitals Complex in Ile-Ife where ages were between 18 and 60 years. Also two focus group discussion sessions were held with 10 males and 10 females living with HIV and currently on ART. Furthermore, in-depth interviews were conducted on three purposively selected healthcare givers (an experienced nurse, a doctor and a pharmacist) in the clinic. The quantitative data were analyzed using descriptive statistics such as tables and percentages and inferential statistics such as Chi Square and cross-tabulations. The qualitative data were analyzed in themes based on the objectives. The findings from the study indicated level of adherence to ART was 89.0% among the respondents. There was a statistically significant relationship (χ 2 = 22.14; p < 0.01) between social and family supports and the degree of adherence to ART among PLWHA. There was a statistically significant relationship between level of adherence and respondents' age (χ 2 = 66.05, p < 0.05). The older the respondents' age, the higher the level of adherence to ART. Also the relationship between educational level and adherence to ART was explored and found to be statistically significant (χ 2 = 26.04, p < 0.05). Adherence is inversely proportional to educational attainment. Nutrition, polygyny, difficulty in financing transportation fare to the clinic, unemployment, drug hawkers, religion, excuse duty from work and waking up very early were highlighted as socio-cultural barriers to adherence to ART. Fear of death, strong family support, religious belief, not seeking alternative treatment, absence of rituals and perceived improved health status were identified as very strong facilitators to adherence. The study concluded that socio-cultural factors exert very strong influences on PLWHA's adherence to antiretroviral therapy.