Officers said the Latvian, who had been forced to deliver charity packages across the central belt and in the east, was found in the course of 15 full-scale anti-slavery operations that are currently under way.
It came after local people who had come in to contact with the teenager expressed concerns about her demeanour.
Details emerged as the new single force, working closely with Europol, doubled the number of crime reports made to fiscals for alleged trafficking to nine so far this financial year. The figure stood at four in the same period of 2012-13.
Police Scotland's National Human Trafficking Unit, set up along with the new force last April, has also had its first international joint investigation team - with colleagues in Poland and London - endorsed by Europol.
Officers from the unit will now probe how 40 Poles were trafficked into the UK as labour in an operation that underscores trafficking is not solely supplying Scotland's booming trade in prostitutes working from private accommodation.
The unit was created amid significant concerns, especially from women's and children's groups, about the exploitation of foreign nationals as prostitutes, domestic servants and forced labourers.
This week the UK's National Crime Agency said there had been 99 potential victims of trafficking last year, according to its National Referral Mechanism (NRM) - up from 96 in 2012 and 93 in 2011.
Police Scotland, which referred one-third of those cases, believes the real numbers are higher. Assistant Chief Constable Malcolm Graham, who is responsible for the trafficking unit, said: "We've got evidence and intelligence of the scale of the problem in Scotland being far wider.
"Clearly, human trafficking by its very nature devastates individuals. But it is highly unlikely that people are going to know that it's going on and go and look for it. The NRM's figures are still the tip of the iceberg in terms of what we know is going on."
Mr Graham said 40 potential adult trafficking victims were identified during a police operation in Scotland last year. He said only one elected to stay in UK and sign up for the scheme.
Scottish police are currently understood to be "progressing" a major cross-continent investigation involving Europol and law enforcement in several countries. But most of the 15 operations under way involve overseas forces.
Details of the 14-year-old Latvian's case have emerged in a new Scottish Police Authority (SPA) report.
It said: "Inquiries revealed that she had been trafficked into Scotland to be used to deliver charity collection packages in and around central and east Scotland.
"Two people were charged with trafficking offences and the victim was safely returned to her home country via the Latvian authorities."
Another man has also been charged with trafficking and a second is being sought on warrant after another Latvian, aged 37, escaped from a house in Glasgow, the SPA report said.
The woman, who had thought she was getting a paid job, had been forced to clean the home after her passport was seized by men who met her at Prestwick Airport.
MSPs are about to vote on a new criminal justice bill that includes the new offence of trafficking as an aggravation to other crimes as well as the abolition of corroboration.
Scrapping the age-old Scots Law safeguard, Mr Graham said, "would assist in some of the cases to see where there is a high quality case [as] there might not always be a sufficiency of evidence using the current laws around corroboration."