We aimed to assess the perceived impact of the lockdown, imposed to control the spreading of COVID-19, on the adherence of Italian celiac disease (CD) subjects to the gluten-free diet by a web-based survey. A total of 1983 responses were analyzed, 1614 (81.4%) by CD adults and 369 (18.6%) by parents/caregivers of CD children/adolescents. The compliance with the GFD was unchanged for 69% of the adults and 70% of the children, and improved for 29% of both. The factors increasing the probability to report stricter compliance were the presence of CD symptoms in the last year before the lockdown (odds ratio (OR) 1.98, 95% confidence interval (CI) 1.46-2.26), a partial usual adherence to gluten-free diet (GFD) (OR 1.91, 95% CI 1.2-3.06), and having tried recipes with naturally gluten-free ingredients more than usual (OR 1.58, 95% CI 1.28-1.96) for adults; the presence of CD symptoms in the last year (OR 2.05, 95% CI 1.21-3.47), still positive CD antibodies (OR 1.89, 95% CI 1.14-3.13), and other family members with CD (OR 2.24, 95% CI 1.3-3.85) for children/adolescents. Therefore, the lockdown led to a reported improved adherence to the GFD in one-third of the respondents, in particular in those with previous worse disease control, offering the opportunity to avoid sources of contamination/transgression and increase the use of naturally gluten-free products.