The deceased has been identified as Vidyaraj, student of a government school near his house in southwest Delhi's Naraina area, police said.
"He allegedly hanged himself with a belt in his residence and left no suicide note. From preliminary investigation, it has emerged that he was under pressure for pursuing MBBS after school," a senior police official said.
Vidyaraj was a student of science stream and scored around 60 per cent marks in the class 12th board exams.
His father is a vendor in Naraina and mother a housewife.
The incident was reported around 1.40 PM when the boy was alone at home. A police team was rushed to the spot and his relatives were questioned, following which the sequence of events came to light.
An inquest had been initiated, the official added.