Olivarius is a co-founder of the trans-Atlantic law firm
AO Advocates, which represents victims of childhood sexual abuse, and chair of the executive committee and senior partner at
McAllister Olivarius. As a lawyer, she is known for representing victims of
sexual harassment and sexual assault. This has included representing victims of
nonconsensual pornography and other internet-based privacy violations, such as a precedent-setting case representing YouTube personality
Chrissy Chambers. Olivarius represented a group of professors and students at the
University of Rochester, of which two plaintiffs, Celeste Kidd and Jessica Cantlon, were named "Persons of the Year" by
Time magazine in its cover story "Silence Breakers" in 2017. Olivarius has represented victims of other forms of discrimination. In 2017, she represented a British Sikh couple, who were turned away from an adoption agency because only white children were available, in a case against
The Royal Borough of Windsor and Maidenhead that was supported by the
Equality and Human Rights Commission. In 2017, the British academic journal
Nature named Olivarius as one of "Nature’s 10" people who mattered in science because of her work fighting sexual harassment at universities. That year she also became a Donaldson Fellow at the Yale School of Management, citing her as "a groundbreaking civil rights litigator". Olivarius established The Rhodes Project to study the lives and careers of Rhodes Scholars. In 2012, the
American Civil Liberties Union (ACLU) included her in its list of nine most influential people in the history of
Title IX. She received the Yale Women Lifetime Achievement Award from the Yale Alumni Association in 2019.
Nelson Mandela praised Olivarius as "a lawyer who has advised me well and who has courageously advanced the cause of justice, and improved life opportunities, for hundreds of millions of women, blacks and disadvantaged, worldwide." She has served on the boards of
openDemocracy,
Autistica, and Women Moving Millions and is a founding member of the UK
Women's Equality Party. In December 2022, Olivarius was approved as Honorary
King's Counsel for her "leading role in the fields of women's rights, sexual harassment and sexual abuse. On 31 December 2022, she was awarded
Officer of the Order of the British Empire (OBE) in the
2023 New Year Honours for services to justice and to women and equality. == Personal life ==