"Per our private information policy, any Tweets that include personally identifiable information about any individual, including the alleged whistleblower, would be in violation of the Twitter Rules", said company spokeswoman Katie Rosborough.
President Donald Trump has pushed for the release of the whistleblower's name, but United States officials and many media outlets have refrained from printing it.
"You know what we used to do in the old days when we were smart with spies and treason, right?"
The ruling is in reaction to a publication of a Breitbart news article which claimed to identify the whistleblower's identity on the platform.
The tech giants' decisions come as Washington is gripped by impeachment drama, sparked by allegations that President Trump sought to pressure his Ukrainian counterpart to launch investigations into Joe Biden - a rival in the upcoming presidential election - and his son, Hunter. The whistleblower filed a complaint about the call, which has led into an impeachment inquiry for the president.
The federal Whistleblower Protection Act of 1989 prohibits the U.S. Office of Special Counsel from disclosing a whistleblower's identity, but does not extend to people outside the government.
"Any mention of the potential whistleblower's name violates our coordinating harm policy, which prohibits content 'outing of witness, informant, or activist, '" said Facebook in a statement. The president responded in a news conference Friday by suggesting the person should be tried for treason. Last week, Twitter said it is banning all political ads from its service, in sharp contrast to Facebook, which continues to defend running paid political ads, even false ones, as a free speech priority. "To that end, I am deeply troubled with Facebook seeking to profit from advertising that would place someone in harm's way".
This is not the first issue on which Twitter and Facebook have split.
Facebook has recently defended taking a hands-off approach to political content, particularly with ads, which CEO Mark Zuckerberg argues should not be fact-checked by Facebook.