Background Phase angle (PhA), measured by bioelectrical impedance analysis (BIA) has been studied as an indicator of survival in people living with HIV (PLWH). However, it remains unclear whether PhA is associated with malnutrition or low CD4+ T-cell counts. Objective In this study, we assessed the discriminative capacity of PhA for malnutrition detection using Global Leadership Initiative on Malnutrition (GLIM) criteria in PLWH, aiming to propose cutoff points for this population. Methods This retrospective observational study included 427 adult PLWH (13% female). Participants were classified according to malnutrition status by using GLIM criteria. Body composition was assessed by using BIA. CD4+ T-cell counts were determined by flow cytometry. Results According to GLIM criteria, 30% of the participants were malnourished. Multivariate regression analysis showed that PhA (adjusted odds ratio [OR], 0.10; 95% CI, 0.05-0.18; P < 0.001), fat-mass percentage (adjusted OR, 0.86; 95% CI, 0.82-0.90; P < 0.001), and male sex (adjusted OR, 0.26; 95% CI, 0.09-0.76; P = 0.013) were independently associated with malnutrition. A PhA cutoff of 5.45 degrees in men and 4.95 degrees in women may predict malnutrition with sensitivity and specificity >70%. Conclusion PhA could be a valid, useful, and simple predictor of malnutrition in PLWH.