We encountered a 5-year-old girl with acute onset of alternating, comitant esotropia in the absence of diplopia and other neurologic findings. She did not have any refractive error and seen bilateral papilledemas in fundus examination, magnetic resonance imaging (MRI) of the head was performed. A large cerebellar astrocytoma and moderate hydrocephalus was identified and successfully resected. The onset of comitant esotropia in a child can be the first sign of a cerebellar tumor without any other neurologic signs and symptoms.