The British broadcaster engaged in a "serious breach" of industry standards by not revealing that the presenter of a programme about Gaza was the child of a Hamas representative, as ruled by regulatory body Ofcom.
An inquiry by the broadcasting watchdog into the programme Gaza: How to Survive a Warzone has found that the programme was "significantly deceptive".
The BBC's director general had previously apologised, saying there had been "a serious error in relation to truthfulness".
Ofcom has ordered the BBC to broadcast a peak-time declaration about its decisions.
"As this represents a serious breach of our code, we are instructing the BBC to transmit a message of our determinations against it on the BBC's second channel at 21:00, with a schedule to be confirmed," the statement read.
'Potential to Undermine Trust'
The watchdog's announcement said: "The inquiry we conducted found that the documentary's lack of disclosure that the presenter's male guardian occupied a post in the Hamas-run government was significantly deceptive.
"Consequently that the audience did not have vital facts which may have been highly relevant to their evaluation of the presenter and the content he provided.
"Trust is at the heart of the relationship between a television network and its viewers, particularly for a state-funded media outlet such as the BBC.
"This error had the potential to erode the significantly high amounts of credibility that the public would have placed in a factual film from the broadcaster about the conflict in Gaza."
The documentary was removed from the online platform in last February after the boy's personal associations were revealed, and in the month of July an broadcaster's internal assessment determined it infringed the corporation's content policies on factual correctness.
A BBC spokesperson stated: "The regulator's decision is in accordance with the findings of the corporation's inquiry, that there was a major oversight in the film in relation to the broadcaster's journalistic policies on factual correctness, which corresponds to regulation 2.2 of Ofcom's Broadcasting Code.
"We have apologised for this and we agree with Ofcom's decision in its entirety. We will adhere to the penalty as soon as the timing and wording are finalised."