Respicius Mtazangira caned and hit Sperius Eradius with a blunt object at their school in Bukoba town in north-western Tanzania last August after accusing the boy of a stealing a handbag that had gone missing.
Sperius denied the allegation, but Mtazangira still proceeded to assault him.
In his ruling on Wednesday, High Court Judge Lameck Mlacha convicted Mtazangira of murder, but acquitted fellow teacher Heriet Gerald.
According to BBC, Nine witnesses – including pupils – testified during their trial. A medical report presented to court showed that the beating had caused the child’s death.
Mtazangira’s lawyer was quoted by local media as saying that he did not rule out an appeal against the verdict.
Tanzania last carried out the death sentence in 1994.
President John Magufuli indicated in 2017 that he opposed executions.
“I know there are people who convicted of murder and waiting for death penalty, but please don’t bring the list to me for decision because I know how difficult it is to execute,” he said.