Samuel Loyd (January 30, 1841 – April 10, 1911), born in Philadelphia and raised in New York, was an American chess player, chess composer, puzzle author, and recreational mathematician.

As a chess composer, he authored a number of chess problems, often with interesting themes. At his peak, Loyd was one of the best chess players in the US, and was ranked 15th in the world, according to chessmetrics.com.

He played in the strong Paris 1867 chess tournament (won by Ignatz von Kolisch) with little success, placing near the bottom of the field.

Following his death, his book Cyclopedia of 5000 Puzzles was published (1914) by his son. His son, named after his father, dropped the "Jr" from his name and started publishing reprints of his father's puzzles. Loyd (senior) was inducted into the US Chess Hall of Fame.

Loyd is widely acknowledged as one of America's great puzzle-writers and popularizers, often mentioned as the greatest—Martin Gardner called him "America's greatest puzzler", and The Strand in 1898 dubbed him "the prince of puzzlers". As a chess problemist, his composing style is distinguished by wit and humour.