Ernest Ranglin O.D. (born 19 June 1932, Manchester, Jamaica) is a Jamaican guitarist and composer. Best known for his session work at the famed Studio One, Ranglin helped give birth to the ska genre in the late 1950s. Some credit Ranglin with the invention of the core style of guitar play (sometimes known as "scratching") found in nearly all ska music.

Ranglin played on many classic Jamaican recordings, and he performed with artists such as Jimmy Cliff, Monty Alexander, Prince Buster, The Skatalites and the Eric Dean's Orchestra. He has also explored other styles of music, notably blending jazz and reggae. As child, Ranglin had two uncles who played guitar and ukulele. After watching them play, he practiced on their instruments, and stood in for one of them when they failed to turn up for a recording session, impressing his other uncle so much that he was given the instrument for his seventh birthday. He built his own guitar using a sardine can and wires, before progressing to a real one. He moved with his family to Kingston, where he was educated at Providence, Kingston Senior School, and Bodin College. While still in his teens, he began performing live, locally and in the Bahamas, often with the young Monty Alexander. Charlie Christian was an early influence. Aged 15, he joined the Val Bennett band, and went on to play with the Eric Deans band and Count Boysie. By the early 1950s, Ranglin had become a proficient jazz guitarist and toured overseas. In 1958, Chris Blackwell recorded a Ranglin single, which was one of the first releases on Blackwell's R&B label, and a live album split between Ranglin and Lance Haywood was the first to be released by Blackwell. Around 1959, he joined Cluett Johnson's band the Blues Blasters, recording several tracks for Coxsone Dodd at Studio One, including "Shuffling Jug", regarded as one of the first ska recordings. In 1962, the James Bond film Dr. No was filmed in Jamaica. While Byron Lee & the Dragonaires appeared in the film, the soundtrack recordings were actually made by Ranglin. In 1964, Ranglin played guitar on singer Millie Small's "My Boy Lollipop", the first Jamaican song to achieve international success.