Jackknife may refer to: Pocketknife or jackknife, a compact, foldable knife Jackknife Bar, Portland, Oregon, U.S. Jackknifing, a type of crash with articulated vehicle combinations
Film and television Jacknife, a 1989 American film by David Jones "Jack Knife", an episode of NCIS Jackknife, a character on Superjail!
Athletics and sports Jackknife (exercise), an abdominal exercise Jackknife, a kicking move involving 540-degree rotation Jackknife, a type of high dive Jackknife hold, a pinning move in professional wrestling
Other uses Jackknife (statistics), a resampling technique in statistics Jackknife clam, common name for several species of bivalve mollusc
See also Jackknife Bascule Bridge, a bridge in Thunder Bay, Ontario, Canada The Jack-Knife Man, a 1920 film