Human immunodeficiency virus (HIV)-Mycobacterium tuberculosis (MTB) co-infection has become a pressing global public health problem. Although tuberculosis (TB) is both treatable and curable, it has been exacerbated by the HIV/acquired immune deficiency syndrome (AIDS) epidemic. HIV-MTB co-infected patients have a variety of disease-specific, and treatment-related factors that can adversely affect their treatment outcomes. This study was conducted to assess the outcomes of TB treatment and its associated factors among HIV-MTB co-infected patients in Sichuan, Southwest China. A retrospective study was performed on HIV-MTB co-infected patients who were diagnosed and registered in TB designated hospitals in Sichuan from January 1, 2016, to December 31, 2020. Data were collected from patients’ electronic medical records regarding their demographic, clinical, and social support information, and categorical data, such as sex, were reported using numbers and percentages. χ2 and t-tests were conducted to compare groups in relation to different levels of medical institutions. A binary logistic regression model was used to identify the factors associated with unsuccessful TB treatment outcomes. For logistic regression analysis performed using an α of 0.05, odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for various risk factors. A total of 3677 registered HIV-MTB co-infected patients were enrolled. After adjusting for other variables, male, advanced age, receiving TB treatment at the municipal medical institution, being diagnosed with external pulmonary TB, referral or tracing, being sputum smear positive, not initiating antiretroviral therapy (ART) and not using fixed-dose combinations were the main risk factors for treatment failure of HIV-MTB co-infected patients in Sichuan province. Sex, age, hospital level, patient source, other diagnostic factors (e.g., sputum smear results, anatomical site of TB), and factors of therapeutic schemes (e.g., antiretroviral therapy, fixed-dose combinations) may serve as risk factors to estimate the likely treatment outcome of HIV-TB co-infection.