"Two years ago, a mentally ill young man shot me in the head, killed six of my constituents, and wounded 12 others," Giffords, D-Ariz., wrote on AmericansForResponsibleSolutions.org. "Since that terrible day, America has seen 11 more mass shootings -- but no response from Congress to prevent gun violence."
The website also features a commentary written by Gifford and her husband, retired astronaut Mark Kelly, published in USA Today Tuesday.
"This country is known for using its determination and ingenuity to solve problems, big and small. Wise policy has conquered disease, protected us from dangerous products and substances, and made transportation safer," the commentary said. "But when it comes to protecting our communities from gun violence, we're not even trying -- and for the worst of reasons."
The commentary said the website "will invite people from around the country to join a national conversation about gun violence prevention, [and] will raise the funds necessary to balance the influence of the gun lobby."
Giffords and Kelly last week visited affected families in Newtown, Conn., in mourning after December's mass shooting. A gunman killed 27 people, including 20 children, before committing suicide.
Giffords retired from Congress in 2012 to focus on recuperating after she was shot in the head in January 2011 at a congressional meet-and-greet outside of a Tucson grocery store. She was among the 13 injured; a 9-year-old girl and a federal judge were among the six dead.
Kelly has said he and Giffords were prepared to launch fundraising efforts and call for specific restrictions on high-capacity weapons, The Wall Street Journal reported Monday. The push came after they met with gun-control advocates and others, people knowledgeable about the meetings said.