This study examined the influence of socio-demographic characteristics on depression and psychological well-being among selected people living with HIV/AIDS attending Kubwa General Hospital, Abuja. A cross-sectional survey design was adopted, involving 177 PLWHA receiving care at Kubwa General Hospital. Depression and psychological well-being were assessed using standardized measures, while socio-demographic data were collected through a structured questionnaire. Chi-square analyses were employed to examine associations between socio-demographic variables and depression as well as psychological well-being, while Multivariate Analysis of Variance (MANOVA) was used to determine the effect of age on depression and psychological well-being. Findings revealed that age, marital status, family type, educational qualification, and job status were significantly associated with levels of depression (p < .05). Older respondents, particularly those aged 48–55 years, divorced or widowed individuals, respondents from polygamous families, and those with unstable employment reported higher levels of depression. In contrast, sex, religion, and job tenure showed no significant association with depression. For psychological well-being, age emerged as the only socio-demographic factor with a significant association (p < .001), with younger respondents reporting poorer well-being. MANOVA results indicated a significant multivariate effect of age on depression and psychological well-being, with a strong univariate effect observed only for psychological well-being. Conclusion: The study underscores the critical role of age and selected socio-demographic factors in shaping mental health outcomes among PLWHA. Integrating age-sensitive and socio-demographically informed psychological interventions into HIV care services is recommended to enhance mental health and overall quality of life for this population.