Evidence on unnecessary antibiotic use in children with acute viral gastroenteritis (AGE) is scarce. We characterized the extent and correlates of antibiotic use among children hospitalized with viral AGE. A single-center study enrolled children aged 0-59 months hospitalized for AGE between 2008 and 2015 in Israel. Information was collected on laboratory tests, diagnoses, antibiotic treatment, and rotavirus vaccination. Stool samples were tested for rotavirus antigen, GII-norovirus, and stool cultures were performed for bacterial enteropathogens. Data from 2240 children were analyzed. Rotavirus vaccine was given to 79% of eligible children. Rotavirus test was performed on 1419 (63.3%) children. Before the introduction of universal rotavirus vaccination (2008-2010), rotavirus positivity in stool samples was 37.0%, which declined to 17.3% during the universal vaccination years (2011-2015). Overall, 1395 participants had viral AGE. Of those, 253 (18.1% [95% CI 16.1-20.2]) had unnecessary antibiotic treatment, mostly penicillin 46.6%, ceftriaxone 34.0% and azithromycin 21.7%. A multivariable analysis showed an inverse association between rotavirus vaccination and unnecessary antibiotic treatment (odds ratio = 0.53 [95% CI 0.31-0.91]), while positive associations were found with performing chest-X-ray test (3.00 [1.73-5.23]), blood (3.29 [95% CI 1.85-5.86]) and urine cultures (7.12 [3.77-13.43]), levels of C-reactive protein (1.02 [1.01-1.02]) and leukocytes (1.05 [1.01-1.09]). The results were consistent in an analysis of children with laboratory-confirmed rotavirus or norovirus AGE, or after excluding children with CRP > 50 mg/L. In conclusion, antibiotic prescription was common among hospitalized children with viral AGE, which was inversely related to rotavirus vaccination, possibly due to less severe illness in the vaccinated children.