The public service broadcaster was found to have committed a "significant breach" of media regulations by failing to disclose that the presenter of a programme about Gaza was the offspring of a Hamas official, according to regulatory body Ofcom.
An probe by the media regulator into Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had earlier expressed regret, stating there had been "a major oversight in relation to truthfulness".
Ofcom has directed the corporation to broadcast a evening announcement about its findings.
"Given this constitutes a significant violation of our regulations, we are directing the broadcaster to broadcast a message of our findings against it on BBC2 at 21:00, with a date to be finalised," the regulator stated.
'Potential to Damage Trust'
The watchdog's announcement stated: "The inquiry we conducted determined that the documentary's lack of disclosure that the narrator's parent occupied a role in the Hamas-run administration was significantly deceptive.
"Consequently that the viewers did not have essential details which may have been highly relevant to their evaluation of the narrator and the details he presented.
"Confidence is at the center of the relationship between a media organization and its public, especially for a public service broadcaster such as the BBC.
"This error had the risk to undermine the very considerable levels of credibility that viewers would have placed in a BBC factual programme about the Israel-Gaza war."
The documentary was withdrawn from iPlayer in February after the boy's personal associations were revealed, and in the month of July an internal BBC review found it violated the corporation's journalistic standards on truthfulness.
A representative for the broadcaster said: "The regulator's decision is in agreement with the conclusions of Peter Johnston's review, that there was a serious error in the film in relation to the corporation's content standards on factual correctness, which aligns with regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with the authority's determination in complete. We will follow the sanction as soon as the timing and wording are determined."
