The organisation said the DreamWorks film is "irresponsible, counterproductive and harmful", reported the Wrap.
The memo cites that the film only tells one side of the story because it is based on two books which were "written by people who had personal and legal disputes with" the organisation.
The film sourced material from Daniel Domscheit-Berg's "Inside WikiLeaks: My Time with Julian Assange at the World's Most Dangerous Website" and Guardian journalists David Leigh and Luke Harding's "WikiLeaks: Inside Julian Assange's War on Secrecy."
The memo also disputes a line in the script that asserts information WikiLeaks leaked in 2011 "exposed over 2000 confidential sources around the world".
WikiLeaks said the film was "a work of fiction masquerading as fact." They also reviewed the film on Twitter.
"As WikiLeaks was never consulted about the upcoming Hollywood film on us, we've given our advice for free: It's bad," the post reads besides providing a link to a more detailed account on their website.