Ánh Quang "Joseph" Cao (/ɡaʊ/ GOW; Vietnamese: Cao Quang Ánh; born March 13, 1967) is a Vietnamese-American politician who was the U.S. representative for Louisiana's 2nd congressional district from 2009 to 2011. A member of the Republican Party, he is the first Vietnamese American and first native of Vietnam to serve in Congress.

Cao was the only Republican congressman to vote for the draft Obamacare, known as Patient Protection and Affordable Care Act, in November 2009.

In April 2011, Cao announced his candidacy for the office of Attorney General of Louisiana, but in September 2011 he pulled out of the race. In December 2015, he announced that he would run for the open U.S. Senate seat being vacated by retiring fellow Republican David Vitter in 2016. As Cao finished eleventh in the primary, he did not place high enough to advance to the general election.

Ánh Quang Cao was born in Saigon, South Vietnam in 1967 as the fifth of eight children to My Quang Cao (1930–2010), a lieutenant in the South Vietnamese Army and Khang Thi Tran (born 1935). He was captured by the North Vietnamese Army in 1975 at the end of the Vietnam War. His mother did not immediately flee South Vietnam, but sent Anh Cao and two siblings to escape with their uncle. She stayed in the country with five of Cao's siblings. She was allowed to visit her husband only five times during the seven years he was imprisoned in a Communist "re-education camp".

In 1975 Anh Cao was eight years old when he, his siblings and his uncle arrived as refugees in the United States, where they were resettled in Houston, Texas. After being released in 1982 from prison camp, Cao's father joined his family in Houston. He suffered from post-traumatic stress disorder (PTSD) and diabetes.

Cao and his family were raised as Catholics. He studied for several years after college to become a priest. He attended public schools and graduated from Jersey Village High School in Houston. He earned a Bachelor of Science degree in physics at Baylor University in Waco, Texas. He studied as a Jesuit seminarian for six years, but withdrew when he concluded that the ministry was not his calling. He earned a Master of Arts in philosophy from Fordham University in New York City, and in 2000 his J.D. from Loyola University School of Law in New Orleans. While in law school, Cao also taught undergraduate courses in philosophy at Loyola.

Cao used his legal training and experience in immigration issues. For a period he taught at a parochial school in Virginia. He volunteered at Boat People SOS (BPSOS) to assist Vietnamese refugees and immigrants and help organize Vietnamese-American communities in the state toward self-sufficiency. He served as a board member of BPSOS from September 1996 to March 2002. After working with Waltzer & Associates, Cao opened his own law practice in New Orleans specializing in immigration law.

Dismayed by the government response to the disaster following Hurricane Katrina, Cao became more involved in politics. He soon became involved in leading New Orleans East residents to oppose a landfill in their area.