The victim, in her 20s, was not injured but was shocked and distressed by what happened, Scotland Yard said, The Telegraph reported.
She was walking in Haringey, north London, with a woman friend at around 7.30pm on Wednesday when the attack happened.
As they crossed the road by The College of Haringey, Enfield and North East London, she was approached from behind by two men.
The Metropolitan Police said one of them pulled down the hijab she was wearing before both fled the scene.
Police in Haringey are appealing for witnesses and information about the incident.
The first suspect is described as white, in his late 20s or early 30s, with blonde or ginger shaved hair and stubble.
Police said he was about 5ft 6in and wearing a burgundy hooded top and carrying a Tesco bag in his right hand.
The second suspect was of Mediterranean appearance, in his late 20s or early 30s, and clean shaven, with spiky hair. He wore a grey hooded top.
Det Con Ben Cousin, of Haringey Community Safety Unit, said: "This was a shocking attack in broad daylight in the middle of a busy street.
"Racially and religiously-motivated crimes will not be tolerated. I would appeal to anyone who witnessed this attack to contact police."