Objectives: Italy was affected greatly by Coronavirus disease 2019 (COVID-19), emerging mainly in the Italian province of Lombardy. This outbreak led to profound governmental interventions along with a strict quarantine. This quarantine may have psychosocial impact on children and parents in particular. The aim of this study was to evaluate the impact of 8 weeks COVID-19 quarantine on psychosocial functioning of Italian parents and their children. Methods: In this cross-sectional survey, we included parents and children resided in Italy during the 8 weeks COVID-19 quarantine. We evaluated social and emotional functioning, clinical symptoms possibly related to emotional distress, and change in perspectives using a questionnaire. Results: The majority of 2315 parents (98% mothers) frequently experienced fear of getting ill (92%) and fluctuating moods (84%), the latter showing correlation to experiencing stress due to being in continuous close vicinity to their children (77%, r = 0.33). Parents reported a positive effect on the relationship with their partner (79%) and their children (89%). Irritability in children was frequent (74%) and correlated to parental fluctuating moods (r = 0.40). The vast majority of the participants (91%) reported that their perspectives for the future had changed. Conclusions for Practice: Our findings suggest a profound impact of the COVID-19 quarantine on emotional functioning of parents and their children in Italy. Despite the protective measure of quarantine against national viral spread and subsequent infection, health care professionals should be aware of this emotional impact, in order to develop protective or therapeutic interventions.