Background: Positivity (POS) indicates the proclivity to see life and experiences in a positive light. There is limited research on its effects on individuals with Schizophrenia Spectrum Disorders (SSD). Very little is known about the relationship between POS and daily activities in people with SSD. Aim: The study aims to compare the POS rated by patients with SSD with those obtained in an Italian normative sample matched by age and sex and to use the Ecological Momentary Assessment (EMA) to investigate the association between POS and daily time use (i.e. productive activities, leisure activities), functioning and mood in individuals with SSD. Method: 620 SSD patients were recruited from mental health services in Italy as part of the DiAPAson project. POS, symptom severity, functioning, and quality of life (QoL) were assessed. POS scores were compared to a normative sample of 5,002 Italian citizens. Additionally, a subset of 102 patients underwent 7-day assessments using mobile EMA. Results: People with SSD did not significantly differ from the Italian normative sample in POS levels (0.035, p = .190). POS showed a significant inverse association with support network (−0.586, p = .036) and symptomatology (BPRS −0.101; 95% p < .001; BNSS B = −0.113, p < .001). A significant direct association was found between POS and QoL ( B = 0.310, p < .001) and functioning ( B = 0.058, p < .001). In the subsample using EMA, POS ratings showed significant associations with Positive Emotions ( B = 0.167, p < .001) and Negative Emotions ( B = −0.201, p < .001). Conclusion: People with SSD exhibited comparable levels of POS to the normative sample. Higher POS was linked to better functioning, QoL, fewer severe symptoms, and increased positive emotions. However, it did not relate to increased productivity or engagement in leisure activities. Further research is needed to understand the relationship between POS and time use in individuals with SSD.