The endorsement provides Clinton with yet another data point to contrast herself with Vermont Sen. Bernie Sanders on the issue of guns, something Clinton has been doing since the first Democratic debate in October.
"Hillary Clinton has been a national leader on gun violence prevention for decades," Brady Campaign President Dan Gross said in a statement. "More than any candidate on either side of the aisle, she has the experience, record, and demonstrated commitment to help reach the Brady Campaign's goal of cutting gun deaths in half by 2025."
Gross will speak at Clinton's first event of the day in Ames, Iowa, according to Clinton aides.
Clinton has long been close with the Brady Campaign. In November, the group awarded her with a leadership award named after the late New York Gov. Mario Cuomo and her husband, former President Bill Clinton, signed the Brady Bill in 1993.
But Clinton has been more forceful on the issue of guns since it has become a way for her to knock Sanders, whose gun record is more conservative than most Democrats. Clinton regularly notes that he voted against the Brady Bill five times, including when it was passed in 1993, and voted in 2005 to give gun manufactures protection from liability.
On Monday night in Iowa, Sanders did not say he regrets his 2005 vote.
Though Gross does not mention Sanders in his statement about the Clinton endorsement, it is clear the senator's positions did not meet the group's standards.
"[Clinton] was with us when we passed the Brady Bill in 1993, she took on the corporate gun lobby by fighting the truly evil Protection of Lawful Commerce in Arms Act, and now she's made gun violence prevention a centerpiece of her campaign, supporting a policy that's already saved lives in Iowa -- expanded Brady background checks on gun sales," Gross said.
The endorsement also comes days after Clinton won the endorsement of former Rep. Gabby Giffords and retired astronaut Mark Kelly
, as well as Sybrina Fulton
, the late mother of Trayvon Martin. All three of them decided to back Clinton, in large part, because of her stance on gun control.