The public service broadcaster committed a "serious breach" of industry standards by not revealing that the voice of a programme about Gaza was the child of a Hamas official, as ruled by regulatory body Ofcom.
An inquiry by the media regulator into the documentary titled Gaza: How to Survive a Warzone has determined that the film was "materially misleading".
The chief executive of the broadcaster had previously apologised, stating there had been "a significant failing in relation to truthfulness".
The authority has instructed the BBC to air a evening declaration about its decisions.
"Given this constitutes a major infringement of our code, we are ordering the BBC to broadcast a message of our determinations against it on BBC Two at 9pm, with a timing to be determined," it said.
'Possibility to Erode Credibility'
The authority's report declared: "Our probe concluded that the documentary's failure to disclose that the narrator's male guardian served in a post in the Hamas-controlled government was materially misleading.
"This implied that the viewers did not have essential details which may have been very significant to their assessment of the presenter and the details he shared.
"Confidence is at the heart of the relationship between a broadcaster and its public, particularly for a state-funded media outlet such as the British Broadcasting Corporation.
"This failing had the potential to erode the significantly high degrees of credibility that audiences would have placed in a BBC factual programme about the conflict in Gaza."
The film was withdrawn from the online platform in February after the narrator's family links emerged, and in July an corporation's own inquiry found it breached the broadcaster's editorial guidelines on factual correctness.
A corporation official said: "The regulator's decision is in agreement with the findings of Peter Johnston's review, that there was a major oversight in the documentary in relation to the BBC's Editorial Guidelines on accuracy, which reflects Rule 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we comply with the regulator's ruling in its entirety. We will adhere to the penalty as soon as the timing and language are determined."
