List of Famous people born on April 21st

Piotr Czesław Brożek is a Polish footballer who plays as a left-back or on the left wing.

Jean-Baptiste Biot was a French physicist, astronomer, and mathematician who co-discovered the Biot–Savart law of magnetostatics with Félix Savart, established the reality of meteorites, made an early balloon flight, and studied the polarization of light.

Alan S. Kaufman is an American psychologist and writer known for his work on intelligence testing.

Niall Williams is a New Zealand rugby sevens player and former New Zealand international touch football captain. She is a member of New Zealand's women's national rugby sevens team and was selected for their squad to the 2016 Summer Olympics, where New Zealand claimed the silver medal behind Australia. In touch football she won gold at the 2005 Youth World Cup and silver at the 2011 Touch Football World Cup.

Sir George Cornewall Lewis, 2nd Baronet, was a British statesman and man of letters. He is best known for preserving neutrality in 1862 when the British cabinet debated intervention in the American Civil War.

Oleksiy Valeriyovych Zhuravko was a Ukrainian and Russian politician who was a member of Ukraine's national parliament Verkhovna Rada from 2006 to 2012. He was a member of the pro-Russian Party of Regions from 2006. Zhuravko moved to Russia in 2015. He acquired Russian citizenship and joined the United Russia party in July 2022. He died in September 2022 in a missile attack in Kherson during the Ukrainian southern counteroffensive.