A teacher of the Dinkar Model School, Dhirendra Kumar Dinkar had allegedly thrashed her with a stick after she refused to attend his tuition classes.
Kaushik, who was admitted to the Maharaja Agrasen Hospital on January seven with severe pain in the head, died on Wednesday night.
"She had developed severe chest infection and her brain had got infected at the same time," said Dr M S Gupta, CEO, Maharaja Agrasen hospital.
An FIR had been lodged against the principal and teacher of the school.
Amidst a public outcry, the Delhi government had de-recognised the school.