Blackneck may refer to:

Lygephila pastinum, also known commonly as the blackneck, a species of moth Blackneck garter snake (Thamnophis cyrtopsis), a species of snake Black-necked swan (Cygnus melanocoryphus), a species of bird Dark-shouldered snake eel (Ophichthus cephalozona), also known commonly as the black-neck snake eel