The attack, in Reform Street, Dundee - one of the city’s main shopping streets - was witnessed by a local city councillor, who is now calling on officials to take action.
Independent councillor Ian Borthwick said several gulls targeted the teenager at once, he said: “I had just come to the bottom of Reform Street and there was a girl about 17 or 18 walking across.
“She had something from Greggs in her hands - she wasn’t eating it - when this big seagull swooped down and grabbed it.
“It was over really quickly but I had never seen anyone so scared.”
Mr Borthwick has now written to Dundee City Council’s environment department asking what they can do to prevent seagulls from attacking people in the city centre.
He has also asked the local authority if it has spoken to other councils about any successful measures they have used.
Gulls become particularly aggressive during their summer nesting season.
The birds, usually herring gulls, also attracted to the food available to them in city centres.
A spokesman for Dundee City Council said: “We know that gulls can often be a cause for considerable distress and annoyance and we continually pursue tried and tested as well as innovative solutions to the problems that arise from these birds
“Pest control officers are actively involved in removing eggs and nests throughout the breeding season, which is approximately April to July, and while this action greatly reduces the incidences of aggressive behaviour as well as disrupting and reducing the breeding pattern, it can take between five and seven years for the effect to take hold.”
He added: “Gulls are protected by the Wildlife and Countryside Act 1981. It allows for the destruction of birds under certain circumstances, but this is only permissible where it can be demonstrated they pose a risk to public safety or public health, and only when all other non-lethal methods of control have been investigated and discounted.”
Earlier this week, it emerged that a hawk has had to be drafted in to tackle a seagull invasion at a Scottish secondary school, after pupils and teachers complain of birds swooping on their lunch.
Spiney the Harris Hawk was introduced at the 1100-pupil Perth Grammar School to scare off “scavenging” seabirds after complaints from staff and students.
The bird of prey was used as part of a £7,000 pest control plan to patrol playing fields and car parks after reports that gulls had been dive-bombing pupils and stealing their sandwiches.
Hawks were successfully used to scare off gulls in Arbroath in 2012 after residents complained they were building nests on their rooftops.
Two years ago, Aberdeenshire Council introduced a falconer to chase off menacing gulls in Peterhead town centre.
The plan worked well for the first few days, but by the end of the week-long trial the gulls had returned and appeared to be intimidating the hawk by swooping and diving above it.
In 2003, two robotic birds of prey, known as “Robops” were installed at Fraserburgh. The flapping fibreglass falcons were placed on rooftops but Aberdeenshire Council pulled the plug on the project after the gulls got used to them and were seen sitting beside them.