When it was announced October 21 that the scantily-clad comic book character had been chosen as a figurehead for the feminist campaign, many UN workers protested.
UN spokesman Jeffrey Brez told CNN Tuesday that the project with Wonder Woman will end December 16.
He said the decision was made soon after the launch to end the character's role on that date and that it was not brought forward due to the protest.
"The objective was to reach out to Wonder Woman fans to raise awareness of UN Sustainable Development Goal No. 5. We did that. We are very happy," he said.
Goal 5 seeks to achieve gender equality and empower all women and girls by 2030.
Decision sparked protest
Concerned United Nations staff members created a petition
in October asking UN Secretary-General Ban Ki-moon to reconsider the choice of the comic book character, first created by DC Comics 75 years ago.
The staffers said the comic book character is "not culturally encompassing or sensitive" and was an inappropriate choice at a time "when the headline news in United States and the world is the objectification of women and girls."
They also protested during the ceremony appointing Wonder Woman as ambassador.
On their petition website, they wrote: "Although the original creators may have intended Wonder Woman to represent a strong and independent warrior woman with a feminist message, the reality is that the character's current iteration is that of a large breasted, white woman of impossible proportions, scantily clad in a shimmery, thigh-baring body suit with an American flag motif and knee high boots --the epitome of a pin-up girl."
The petition had attracted more than 44,000 supporters by Tuesday when the announcement was made that Wonder Woman's role would end.
Fans upset by news
The character -- an Amazonian warrior princess -- made her debut in DC Comics in 1941 and the character was played on TV by Lynda Carter during the 1970s.
The film "Wonder Woman" is set to release in the summer of 2017, with Israeli actress Gal Gadot playing the superhero.
The UN has previously used other fictional characters -- including Red from Angry Birds
and Winnie the Pooh -- to promote messages about happiness and friendship.
News that Wonder Woman is being dropped upset some fans of the comic book character -- and another petition
was launched Tuesday by Tara Peterson, a 14-year-old fan campaigning to reinstate her.
Peterson, who lives in Guadalajara, Mexico, told CNN: "I've loved Wonder Woman since I was a kid. I was so happy a couple of months ago when she was made a UN ambassador. She's the kind of character that deserves that."
"No matter how she is dressed or how she looks Wonder Woman's message of peace, justice and gender equality has always remained," Peterson wrote on her petition page, which had attracted more than 700 supporters Tuesday.
The rights to Wonder Woman's image are owned by DC Comics, a subsidiary of Warner Bros.
"Warner Bros and DC Entertainment are extremely pleased with the awareness that this partnership brought to United Nations Sustainable Development Goal #5, as well as elevating the global conversation around the empowerment of women and girls," said DC Comics spokeswoman Courtney Simmons.
"Wonder Woman stands for peace, justice and equality, and for 75 years she has been a motivating force for many and will continue to be long after the conclusion of her UN Honorary Ambassadorship."