Flemming Delfs (born 7 September 1951) is a former Danish badminton player who was world no.

Delfs is especially noteworthy for winning men's singles[1] at the first IBF World Championships held in Malmö, Sweden in 1977.

[2] He dominated that same 1976/1977 season by winning nearly all other noteworthy tournaments, including the All-England Championships.

[4] He played on all four Danish Thomas Cup (men's international) teams between 1972 and 1982, two of which (1973, 1979) reached the championship round before losing to Indonesia.

[5] Tall, with an elegant style and powerful backhand, Delfs was a highly impressive player at his best, but typically had difficulty in the hot, humid conditions he encountered in the Far East.