Henry Chadwick (October 5, 1824 – April 20, 1908) was an English-American sportswriter, baseball statistician and historian, often called the "Father of Baseball" for his early reporting on and contributions to the development of the game. He edited the first baseball guide sold to the public. He is credited with creating box scores, as well as creating the abbreviation "K" that designates a strikeout. He was posthumously inducted into the National Baseball Hall of Fame in 1938.

Chadwick was born on October 5, 1824, in Exeter, England to James Chadwick and his second wife Theresa. His grandfather, Andrew Chadwick, had been a close friend of theologian John Wesley. His father, James Chadwick, was a supporter of the French Revolution who also tutored John Dalton in music and botany. James Chadwick had served as editor of a publication known as the Western Times.

Henry Chadwick was the much younger half-brother of Sir Edwin Chadwick who was born in 1800. Edwin was England's sanitary philosopher who developed environmental measures and laws designed to counteract the effects of the Industrial Revolution. Edwin Chadwick's mother died soon after Edwin’s birth.

Henry Chadwick moved to Brooklyn with his family at the age of 12, in the 1830s. He began to write music and to teach piano and guitar.

In 1848, Chadwick married Jane Botts from Richmond, Virginia. Botts' father Alexander had been president of the Virginia State Council. She was also related to politician John Botts. Chadwick edited John Botts' work titled The Great Rebellion. Chadwick and his wife had three children, Richard Westlake Chadwick, in 1849, Susan Mary Chadwick, in 1851, and Rose Virginia Chadwick, 1853.

Chadwick became a frequent player of cricket and similar ball games such as rounders. He began covering cricket for numerous local newspapers such as the Long Island Star. He first came across organized baseball in 1856 as a cricket reporter for The New York Times, watching a match played between New York's Eagles and Gothams at the Elysian Fields in Hoboken, New Jersey. He focused his attention as a journalist and writer on baseball after joining the New York Clipper in 1857, and was also soon hired on to provide coverage for other New York papers including the Sunday Mercury.

Chadwick was one of the prime movers in the rise of baseball from the 19th century to its popularity at the turn of the 20th century. A keen amateur statistician and professional writer, he helped sculpt the public perception of the game, as well as providing the basis for the records of teams' and players' achievements in the form of baseball statistics. He also served on baseball rules committees and influenced the game itself. He is sometimes referred to as "the father of baseball" because he facilitated the popularity of the sport in its early days. In a more recent view, Schiff suggests that Chadwick was the father of baseball because he nurtured the sport for decades, rather than a claim to have started the American game.

Early baseball had a provision known as the "bound rule", which held that a fielder could catch a batted ball on one bounce and that it would still be recorded as an out. Chadwick was an outspoken critic of the rule for many years, stating that fielders should have to catch a ball on the fly for it to count as an out. In 1864, the bound rule was eliminated for balls hit into fair territory. The bound rule for foul balls persisted into the 1880s.