Andrea Alice Stewart-Cousins (née Stewart; born September 2, 1950) is an American politician and educator from Yonkers, New York. A member of the Democratic Party, Stewart-Cousins has represented District 35 in the New York State Senate since 2007 and served as Majority Leader and Temporary President of that body since 2019. She has served twice as acting lieutenant governor of New York under Governor Kathy Hochul, for 16 days in 2021 and between April and May 2022. Stewart-Cousins is the first Black woman to serve as New York's lieutenant governor, although in an acting capacity. She is the first woman in New York State history to lead a conference in the New York State Legislature and the first female Senate Majority Leader in New York history.

Stewart-Cousins was first elected to the New York State Senate in 2006. She served as a Westchester County Legislator from 1996 to 2006. In 2012, she was chosen by her colleagues to lead the Senate Democratic Conference. After the Democratic Party won a Senate majority in the 2018 elections, Stewart-Cousins became majority leader in January 2019.

Andrea Alice Stewart was born on September 2, 1950, in New York City. She is the daughter of Bob Stewart, a decorated World War II veteran and repairman, and Beryl Stewart, a stenographer and community activist. The Stewart family resided in public housing in Manhattan and the Bronx, and Andrea suffered from chronic asthma.

Stewart-Cousins spent twenty years in the private sector, including thirteen years in sales and marketing with New York Telephone. After New York Telephone was acquired through a merger with Bell Atlantic, she received a buyout and pursued a college degree while working for Gannett. She earned her Bachelor of Science Degree from Pace University in 1986 and later her teaching credentials in Business Education from Lehman College. She received her Masters of Public Administration from Pace University in May 2008 and is a member of Pi Alpha Alpha, the public administration honor society. She also pursued careers in teaching and briefly in journalism before entering public service.

Stewart-Cousins's public service career began in 1992 when she was appointed Director of Community Affairs for the City of Yonkers during Terence Zaleski's term as mayor. In that role, she created an internship program for the hearing-impaired and for children in working families. She also advocated for and contributed to the revitalization of the City of Yonkers and was a founder of the original "Art on Main Street". Stewart-Cousins was a co-creator of "River Fest", a widely attended multi-cultural citywide celebration on the Hudson River in Yonkers.

Prior to her election to the New York State Senate in 2006, Stewart-Cousins served as a Westchester County Legislator representing Yonkers. First elected in 1995, she served from 1996 to 2006. During her tenure, she was elected Majority Whip and vice-chair. Stewart-Cousins authored living wage laws, smoke-free workplace laws, tougher gun laws, laws that prosecute predatory lenders, tax cuts for seniors and veterans, and Westchester County's first human rights laws.

Stewart-Cousins first ran for New York State Senate in 2004, but incumbent Republican Sen. Nicholas Spano defeated her by a margin of 18 votes. In 2006, she challenged Spano again and defeated him. As of 2019, Senate District 35 includes all of the Towns of Greenburgh and Mt. Pleasant, and portions of Yonkers.

Stewart-Cousins voted in favor of same-sex marriage legislation on December 2, 2009, but the bill was defeated. A same-sex marriage law was eventually passed in 2011. Stewart-Cousins is a vocal supporter of abortion rights, and has pushed for legislation to expand abortion access in the State of New York.