The disaster occurred at about 2200 GMT Monday at the Salama School for the Blind in Mukono, southeast of the capital Kampala.
"The cause of the fire is currently unknown but so far 11 deaths as a result of the fire have been confirmed while six are in critical conditions and admitted (to hospital)," the Uganda Police Force said on Twitter.
Police said an investigation had been launched into the cause of the fire but did not specify if the victims were all students at the school.
In November 2018, 11 boys perished and another 20 suffered severe burns in a suspected arson attack at a boarding school in southern Uganda.
Several fires have broken out at schools in the East African nation in recent years.