The social media company said it regards political content as material "that references a candidate, political party, elected or appointed government official, election, referendum, ballot measure, legislation, regulation, directive, or judicial outcome."
The ban prohibits ads by "candidates, political parties, or elected or appointed government officials," the company said on its website. The prohibitions also apply to PACS, SuperPACs and 501(c)(4)s organizations.
The company said news publishers who meet its exemption criteria "may run ads that reference political content and/or prohibited advertisers under our political content policy, but may not include advocacy for or against those topics or advertisers."
Enforcement of the policy is slated to begin on Nov. 22.
The company said violations can be reported "in the Twitter Timeline or through the Help Center Form. Twitter will prioritize and review reported content."
Twitter CEO Jack Dorsey announced the ban last month. The decision stands in marked contrast to Facebook (FB) - Get Report CEO Mark Zuckerberg's defense of running political material on the social network in the interests of free speech even if it's known to be false.
Followings Facebook's quarterly earnings last week, CEO Mark Zuckerberg acknowledged that it will likely be a tough year ahead for Facebook as election season kicks off in earnest.
Shares of Twitter rose 42 cents, or 1.45%, to $29.31 in afternoon trading Friday.