The public service broadcaster was found to have committed a "significant breach" of industry standards by failing to disclose that the voice of a documentary about Gaza was the son of a Hamas representative, according to regulatory body Ofcom.
An inquiry by the media regulator into Gaza: How to Survive a Warzone has found that the film was "substantially inaccurate".
The BBC's director general had already issued an apology, noting there had been "a significant failing in relation to factual correctness".
The authority has ordered the corporation to transmit a prime-time declaration about its conclusions.
"As this represents a serious breach of our regulations, we are ordering the BBC to transmit a message of our determinations against it on BBC2 at 9pm, with a timing to be determined," the statement read.
'Possibility to Undermine Confidence'
The watchdog's report said: "Our probe found that the programme's failure to disclose that the narrator's parent held a position in the Hamas-administered authority was significantly deceptive.
"Consequently that the viewers did not have critical information which may have been extremely pertinent to their judgment of the voice and the information he shared.
"Confidence is at the core of the relationship between a broadcaster and its viewers, especially for a public service broadcaster such as the British Broadcasting Corporation.
"This failing had the risk to damage the significantly high degrees of trust that the public would have invested in a documentary produced by the BBC about the Israel-Gaza war."
The documentary was pulled from iPlayer in February after the narrator's personal associations came to light, and in July an internal BBC review determined it breached the organization's journalistic standards on accuracy.
A corporation official said: "The regulator's decision is in agreement with the conclusions of the internal assessment, that there was a serious error in the film in relation to the corporation's content standards on accuracy, which reflects regulation 2.2 of the regulator's media standards.
"We expressed regret for this and we accept the regulator's ruling in its entirety. We will follow the penalty as soon as the schedule and wording are confirmed."
