The United Grand Lodge of England placed adverts in three national newspapers headlined “enough is enough”, saying it is the victim of misrepresentation.
Chief executive Dr David Staples said he had written to the Equality and Human Rights Commission about concerns its 200,000-plus members are the victims of gross misrepresentation and discrimination.
He said: “Our members shouldn’t have to feel undeservedly stigmatised.
“No other organisation would stand for this and nor should we.”
He added that people may have questions about Freemasonry, and that members would be hosting Q&A sessions across the country.
“I appreciate that you may have questions about who we are and what we do, so why not ask those who know?,” he said.
Last year, the United Grand Lodge of England raised more than £33 million for good causes, he added.