Robert Eugene Byrne (April 20, 1928 – April 12, 2013) was an American chess player and chess author who held the FIDE title of Grandmaster (GM). He won the U.S. Championship in 1972, and was a World Chess Championship Candidate in 1974. Byrne represented the United States nine times in Chess Olympiads from 1952 to 1976 and won seven medals. He was the chess columnist from 1972 to 2006 for The New York Times, which ran his final column (a recounting of his 1952 victory over David Bronstein) on November 12, 2006. Byrne worked as a university professor for many years, before becoming a chess professional in the early 1970s.

Byrne was born in Brooklyn, the son of Elizabeth Eleanor (Cattalier) and Robert Byrne. He and his younger brother Donald grew up in New York City and were among the "Collins Kids", promising young players who benefited from the instruction and encouragement of John W. Collins. Both ultimately became college professors and among the leading chess players in the country. They were part of a talented new generation of young American masters that also included Larry Evans, Arthur Bisguier, and George Kramer.

Robert Byrne's first Master event was Ventnor City in 1945, where he scored a respectable 4/9 to place 8th; the winner was Weaver Adams. He tied 1st–2nd in the Premier Reserves section at the U.S. Open Chess Championship, Pittsburgh, in 1946. College studies limited his opportunities for the next several years; he represented the U.S. in a 1950 radio match against Yugoslavia. In the 1951 Maurice Wertheim Memorial in New York, Byrne scored 6/11, tying for 6th–7th place; this was a Grandmaster round-robin featuring six of the world's top 36 players, and was won by Samuel Reshevsky.

Byrne became an International Master based on his results at the 1952 Chess Olympiad at Helsinki (bronze medal on third board). In that same year he graduated from Yale University. He went on to become a professor of philosophy at Indiana University, and his academic career left him little time for chess. He did represent the U.S. in team matches against the Soviet Union at New York in 1954 (losing 1½–2½ to Alexander Kotov), and Moscow in 1955 (losing ½–3½ to Paul Keres).

Byrne shared 4th–7th positions at the 1957 U.S. Open Chess Championship in Cleveland with 9/12, a point behind joint winners Bobby Fischer and Arthur Bisguier. Byrne did not play in his first U.S. Chess Championship until the age of 30 in 1958–59, placing tied 9th–10th with 4/11; the winner was Bobby Fischer. But Byrne improved dramatically the next year in the same event to place 2nd with 8/11, ahead of Reshevsky and Pal Benko, as Fischer won again.

In 1960, Byrne increased his serious play, winning the U.S. Open Chess Championship at St. Louis, and taking a silver medal on third board at the Olympiad in Leipzig. A poor result of 8th–11th place in the U.S. Championship 1960–61, with only 4½/11, was balanced by his fine tie for 2nd–5th places at Mar del Plata 1961 with 11½/15, behind winner Miguel Najdorf. On that same South American trip, he dominated a small but strong event at Santa Fe with 6½/7, ahead of Miroslav Filip, Aleksandar Matanović, and Héctor Rossetto. In the U.S. Championship of 1961–62, he tied for 2nd–3rd places on 7/11, half a point behind Larry Evans. He placed 6th in the U.S. Championship 1962–63 with 6/11, as Fischer won again. In the U.S. Championship 1963–64 he again placed 6th with 5½/11, as Fischer defeated Byrne brilliantly in 21 moves and won the tournament with a perfect score. Of his game against Fischer, Byrne wrote: "The culminating combination is of such depth that, even at the very moment at which I resigned, both grandmasters who were commenting on the play for the spectators in a separate room believed I had a won game!"

In 1964, Byrne's third-place finish at the Buenos Aires tournament (behind Paul Keres and World Champion Tigran Petrosian), with 11½/17, made him an International Grandmaster. Byrne shared 2nd–3rd places in the U.S. Championship 1965–66 with 7½/11; Fischer won again, but Byrne defeated Fischer in their individual game. He shared the 1966 U.S. Open title with Pal Benko at Seattle. He scored 4½/11 for a shared 8th–10th place in the U.S. Championship 1966–67, with Fischer winning. Byrne qualified for his first Interzonal tournament, Sousse 1967, but scored just 7½/22, far short of advancing.

By the late 1960s he was playing chess semi-professionally. He won the 1972 U.S. Championship; after tying with Samuel Reshevsky and Lubomir Kavalek in the tournament proper, Byrne won the 1973 playoff at Chicago. Subsequently, scoring 12½/17, Byrne achieved his career highlight of third place at the Leningrad Interzonal in 1973, which made him only the fourth American (after Reshevsky, Bobby Fischer, and Pal Benko) to qualify for the Candidates Tournament (part of the world chess championship process). However, he lost his first-round Candidates match to former world champion Boris Spassky by 1½–4½ at San Juan, Puerto Rico, in 1974.