The group, which supports persecuted Christians worldwide, said it was delighted that the Pakistan high court judge had thrown her case out this week but added that her life was still at risk from extremists.
In the past, there have been reports of blasphemy cases being overturned only for the accused to be released and face "mob justice" at the hands of radicals.
"Rimsha's life is still in danger," said Release partners. "There is no future for Rimsha and her family in Pakistan, as we have seen from previous cases. They would have to live in hiding for their security."
Rimsha, who has learning difficulties, was accused in August of burning pages of the Koran.
Chief Justice Iqbal Hameed-ur Rehman threw out the case on Tuesday, citing a lack of witnesses to support the allegation.
A Muslim cleric from Rimsha's neighbourhood has been charged with blasphemy amid claims that he desecrated the Koran to fabricate evidence against the teenage girl.
Release partners say: "Rimsha has been released from all blasphemy accusations at an early stage because her case received international intention and the media highlighted the truth. Many other blasphemy cases are also false. What Rimsha's case shows is that blasphemy charges are often registered due to personal enmity and for personal interests."
Release chief executive Paul Robinson welcomed her release.
"The international outcry over this case has cast a much needed spotlight over Pakistan's unjust blasphemy laws," he said.
"But this positive progress has come at a high price for a young girl with learning difficulties, and her family.
"We hope this development will have a positive effect on the cases of Asia Bibi and Younis Masih, two Christians who are waiting for their appeals against blasphemy convictions to come to court – after years in custody.
"We also look forward to the Pakistani authorities taking bold and courageous steps to tackle this injustice and reform the blasphemy laws, for the sake of all Pakistani citizens, not just religious minorities."