James Woodward Downey (born 1952) is an American comedy writer, producer, actor and comedian. Downey wrote for over 30 seasons of Saturday Night Live, making him the longest tenured writer in the show's history.

Downey was born in Berkeley, California, and grew up in Joliet, Illinois. After graduating from Joliet Catholic High School, he entered Harvard University, where he wrote for the Harvard Lampoon and later became its president. As a Lampoon writer, Downey created a Cosmo parody featuring a fictitious nude photo of Henry Kissinger on the front cover and invited John Wayne to the campus. He graduated from Harvard in 1974 with a degree in Russian. After graduating, Downey received a one year fellowship to eastern Europe, for which he turned down an invitation by Michael O'Donoghue to be part of the first season of SNL.

Downey is not related to SNL alumnus Robert Downey Jr., whose uncle James B. Downey has been confused with Jim Downey in the past.

In 1976, Downey joined the Saturday Night Live writing staff as its youngest member. He was among the first Harvard Lampoon writers to write for television, at a time when, in the opinion of writer Steve O'Donnell, "the sensibilities of the Lampoon [were] a little closer to the sensibilities of the mass media." Simpsons writer Mike Reiss called Downey "patient zero" of Lampoon comedy writers.

Downey ultimately worked on 27 of the show's first 32 seasons, one of the longest tenures in the show's history. He arrived at Saturday Night Live the same week as Bill Murray with whom he ended up sharing an office overlooking 50th Street, but he mostly began writing at SNL with Al Franken, Tom Davis, and Dan Aykroyd. His first stretch as writer for the show ran from 1976 to 1980, culminating in a brief stint as a featured cast member. By the 1979–1980 season, Lorne Michaels had lost both Dan Aykroyd and John Belushi to feature film careers, causing him to look to writers like Downey, Tom Schiller, Dan Aykroyd's brother Peter, Al Franken, Alan Zweibel, and Tom Davis to fill spots as cast members (along with SNL bandleader Paul Shaffer and newcomer Harry Shearer). Downey left the show in 1980 as part of the mass exodus of writers and actors following Lorne Michaels's departure.

After leaving SNL, Downey became the second head writer of Late Night with David Letterman for a little over a year, from 1982 to 1984, during its formative stages. He is credited with inventing its Top Ten List and contributing to its influential sensibility and attracting other talented writers. Together with Letterman, Downey wrote a week long ongoing joke featuring the "World's Largest Vase."

Downey became head writer for Michaels The New Show in 1984, which flopped and was cancelled after 9 episodes. Downey returned to SNL that same year as a writer with Dick Ebersol producing the show. Michaels returned to the show in 1985, naming Downey as head writer, a new position at the time. As head writer, Downey introduced rewrite sessions on Thursdays, which had not existed during the shows first five years. Downey stayed in that position until the end of season 20 in 1995, after 10 years as head writer (the longest-tenure for an SNL head writer and one of the few writers from the previous season to return to season 21).

Downey was responsible for Norm Macdonald becoming Weekend Update anchor in 1994, and beginning the next year wrote exclusively for that segment of the show after retiring as head writer. Downey and Macdonald subsequently became a team, working away from the rest of the cast and crew.