Deepak Kumar, 21, was shot while leading the party to his bride’s home in the Indian capital on Tuesday evening.
Police said a guest dancing with the wedding party opened fire but a stray round struck the husband-to-be.
“He collapsed and was rushed to a hospital where he was declared dead after midnight,” Nupur Prasad, deputy commissioner of Delhi police, told AFP.
Firing weapons in the air at weddings and other festivities is a common celebration across South Asia.
The practice is illegal in India but remains rife, though fatalities are relatively few.
Prasad said the groom’s family had identified the man who fired the bullet.
“It is an ongoing investigation and we are trying to ascertain the source of his weapon,” he said.
Amit, one of the wedding guests, told the Times of India newspaper there “were a couple of people carrying guns for celebratory firing, which is considered a tradition in the family”.