On arrival in London at a global summit to end sexual violence, the actress dedicated the four-day event to an unnamed and "abandoned" victim of rape in Bosnia.
Foreign Secretary William Hague also announced the UK would pledge a further £6 million to support survivors of sexual violence in conflict.
Mr Hague said it was only a "weak or inadequate man" that abused women - a statement that led to cheers from the crowd.
In a speech that was met with loud applause, Jolie, who is special envoy for the UN High Commissioner For Refugees, said: "We must send a message around the world that there is no disgrace in being a survivor of sexual violence, that the shame is on the aggressor."
She said it was a "myth" that rape was an inevitable part of conflict.
"There is nothing inevitable about it - it is a weapon of war aimed at civilians," the actress said.
"It has nothing to do with sex, everything to do with power."
Jolie told the packed crowd at the opening of the End Sexual Violence in Conflict summit that she had met survivors in countries including Afghanistan and Somalia, and they were "just like us, with one crucial difference".
She said: "We live in safe countries with doctors we can go to when we're hurt, police we can turn to when we're wronged, and institutions that protect us.
"They live in refugee camps, on bombed-out streets, in areas where there is no law, no protection, and not even the hope of justice."
The international community needs to work to make "justice the norm", she said as she called for all armies, peacekeeping troops and police forces to have prevention of sexual violence in conflict as part of their training.
"This whole subject has been taboo for far too long," she said.
Jolie, best known for her role as Lara Croft in the Tomb Raider films, said the stigma of such violence causes survivors to suffer feelings of "shame" and "worthlessness".
"It feeds ignorance, such as the notion that rape has anything to do with normal sexual impulses," she said. "But, most of all, it allows the rapist to get away with it. They feel above the law because the law rarely touches them and society tolerates them."
Speaking as she arrived at the ExCeL conference centre in the capital's Docklands area, Jolie said: "I am so, so happy to be here, it has been long in coming, we have worked on this for quite a while."
She spoke about how she and Mr Hague met a woman earlier this year during a campaigning trip to Bosnia.
"On our way over, we spoke about the women we met recently on our last trip, and in particular one woman, who said she had yet to tell her child she had been raped because she was so humiliated and she could not bring herself to admit it to him.
"And she felt that, having had no justice for her particular crime, in her particular situation, and having seen the man who raped her on the streets, free, she really felt abandoned by the world.
"On the way over, we thought, 'What is she going to think of this day?'. This day is for her."
The Foreign Secretary said he and Jolie began campaigning two years ago because they "believe the time has come to end the use of rape in war once and for all".
Mr Hague and Jolie will co-chair the four-day summit.
The conference - with 117 countries represented - aims to draw up an international agreement on standards for documenting and investigating sexual violence in conflict zones in an attempt to ensure justice for victims.