The British broadcaster was found to have committed a "major breach" of broadcasting rules by not revealing that the voice of a programme about Gaza was the offspring of a Hamas representative, according to UK media regulator Ofcom.
An inquiry by the broadcasting watchdog into Gaza: How to Survive a Warzone has concluded that the documentary was "significantly deceptive".
The head of the BBC had earlier expressed regret, saying there had been "a serious error in relation to accuracy".
The authority has instructed the BBC to air a evening declaration about its decisions.
"As this represents a significant violation of our rules, we are instructing the corporation to broadcast a statement of our conclusions against it on BBC2 at nine o'clock in the evening, with a timing to be determined," it said.
'Risk to Damage Trust'
The regulator's statement stated: "The inquiry we conducted found that the documentary's failure to disclose that the narrator's male guardian held a post in the Hamas-run authority was substantially inaccurate.
"Consequently that the public did not have critical information which may have been very significant to their evaluation of the narrator and the content he provided.
"Confidence is at the center of the bond between a television network and its audience, especially for a national broadcasting corporation such as the public broadcaster.
"This error had the risk to undermine the very considerable amounts of trust that audiences would have invested in a factual film from the broadcaster about the Israel-Gaza war."
The documentary was pulled from the online platform in February after the boy's familial connections came to light, and in the month of July an internal BBC review determined it breached the broadcaster's editorial guidelines on accuracy.
A representative for the broadcaster stated: "The regulator's decision is in line with the results of Peter Johnston's review, that there was a serious error in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which aligns with Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we comply with the regulator's ruling in complete. We will comply with the penalty as soon as the date and language are finalised."
