Background: People with schizophrenia show impairments in metacognitive function, including awareness and monitoring of one's mental processes (Self-Reflectivity (SR)), recognition of the fallibility of one's thoughts, and the ability to infer others' emotions and intentions (Theory of Mind (ToM)). The aim of the present study was to explore whether SR and ToM play a key role in influencing the global functioning of persons affected by schizophrenia. Methods: Twenty persons with schizophrenia were recruited before hospital discharge and compared with 17 controls. Clinical, neurocognitive, and global functioning assessments were performed. The Beck Cognitive Insight Scale was used to assess: (1) Self-Reflectiveness, which allows subjects with psychosis to objectively observe their cognitive distortions, and (2) Self-Certainty, which reflects rigid confidence in their own beliefs (over-confidence). ToM assessment included verbal and non-verbal measures. Results: Our study confirms the semi-independent nature of the metacognitive functions of ToM abilities and the cognitive insight domain. In fact, by multiple regression model analyses, only the Self-Reflectiveness deficit was found to be the best predictor of low global functioning in schizophrenia and represents a target for rehabilitation interventions to remediate the processes that cause fallible interpretations of daily events. Conclusions: Our results encourage a new trend in the cognitive-behaviour therapy of schizophrenia to be complemented with metacognitive approaches. (Contains 3 tables.)