The present invention relates to an insulation displacement connector. One embodiment includes an insulation displacement terminal in which wire insulation displacement portions, to be electrically connected to wire, are formed by cutting and folding, a connector housing for holding the insulation displacement terminal therein and having a holder opening in an area in which the wire insulation displacement portion of the insulation displacement terminal are located, and a wire holder having a pair of upper and lower covers capable of being assembled together by being mounted to the holder opening, wherein the lower cover includes a rotary piece rotatable inward about a proximal end thereof when the lower cover is assembled with the upper cover to clamp or to provide strain relief for the wire in association with the upper cover.