Rationale: The neurotoxic effects of comorbid HIV infection and substance use disorders (HIV/SUD) preferentially impact the fronto-striatal regions of the brain, leading to increased disruption of higher-order executive functions. Poor insight into such neurocognitive deficits (impaired metacognition) tracks with executive dysfunction and is associated with errors in everyday life. We evaluated the efficacy of a brief Metacognitive Training module for neurorehabilitation of HIV/SUD individuals. Design: A between-subjects, randomized design was used to examine the effectiveness of Metacognitive Training among HIV/SUD individuals with current executive dysfunction. To determine the efficacy of the Metacognitive Training compared to an executive strategy (Goal Management Training, GMT), 90 HIV/SUD participants were randomized to: 1) active control (n=30); 2) executive strategy only (i.e., GMT; n=30); or 3) Metacognitive Training plus executive strategy (Meta+GMT; n=30). Following the study condition, participants completed a complex instrumental activities of daily living (IADL) task (Everyday Multitasking Test, "Everyday MT"); additionally, in-vivo metacognitive abilities regarding IADL task performance were evaluated. Results: There was an increasing tendency for better Everyday MT performances across study conditions (Control≤GMT≤Meta+GMT) that approached significance (ps<0.08). Pairwise differences indicated the GMT or Meta+GMT trainings demonstrated small (d=0.20-0.24) benefits in Everyday MT performance compared to the control condition (ps<0.11). HIV/SUD individuals who completed the GMT (in addition to the Meta or not) had significant, medium-sized enhancements in Everyday MT performances compared the control condition (ps<0.05; ds=0.38-0.41); the effect of these enhancements became even larger among those who had poorer dual-tasking capacities prior to training and completed the GMT (ps<0.04; ds=0.83-1.04). Regarding metacognition, although there was no significant study group effect on Global Metacognition, Online Awareness (one of the two components of global abilities) showed a significant positive trend across training condition (Control≤GMT≤Meta+GMT; p=0.04). Among the skills comprising Online Awareness, a tendency toward more elaborate Task Appraisals was observed among HIV/SUD individuals who completed either the GMT or Meta+GMT (versus control; ps<0.07, ds=0.21-0.27). Those who completed the GMT (in addition to the Meta or alone) demonstrated medium, significant benefits of GMT on Task Appraisals compared to the control condition (p=0.01; d=0.50). Conclusions: Our experimental design demonstrated meaningful benefits of a brief GMT executive strategy for everyday multitasking and metacognition among HIV/SUD individuals. Ours are among the first findings supporting a compensatory neurorehabilitation tool in HIV+ individuals and/or substance users.