A hair clip includes a first clip piece and a second clip piece which are complimentarily formed. Each of the first and second clip pieces includes an inclined teeth-like clipping portion formed at a bottom thereof, each inclined clipping portion including a plurality of teeth which are so spaced and dimensioned as to allow smooth lateral opening and closing of the two clipping portions without jamming between the teeth of the clipping portions. The second clip piece has a first end pivotally connected to a first end of the first clip piece. The first clip piece and the second clip piece respectively have a clipping end formed on a second end thereof, the two clipping ends extending in different directions so as to be releasably engaged together.