Deputy Commissioner of Police Rishi Pal said that the incident took place on Friday evening in North Delhi's Rohini when the girl was walking back home after work.
When three on a bike tried to snatch her mobile, the "girl caught hold of one of them and pulled him down from the moving motorcycle and punched him. He was then overpowered with the help of passers-by," Deputy Commissioner Pal said.
Police later apprehended the other two accused, including a juvenile.
Police identified the accused as Sandeep and Vikram Mehra, both residents of Delhi.
The DCP said that the brave girl would be rewarded.