Abstract: A pipe coupling suitable in particular for coupling a pipe of plastic material to a fitting or coupling together a pair of such pipes. The pipe coupling comprises an externally threaded sleeve member formed with one or more inwardly directed protrusions and adapted to receive a pipe to be coupled, an internally threaded collar member into which said sleeve is screwable, at least one of said members being formed or provided with constraining means whereby, with said pipe received within said sleeve the axial movement of said sleeve into said collar results in the protrusions biting into the pipe.