Abstract: A pipe sealing gasket is shown which is designed to be received within a groove provided within a socket end of a thermoplastic pipe. The gasket includes a ring shaped body which, when viewed in cross-section includes a leading nose region and a generally planar lower compression region, the leading nose region being joined to the lower compression region by a leading sloped surface region which forms an alignment ramp to guide a mating spigot end during insertion and which defines an angle .alpha. with respect to a horizontal axis drawn parallel to a central axis of the pipe, the lower compression region being joined to a secondary seal surface by a vertical lip portion which terminates in a trailing surface which defines a second angle .beta. with respect to the horizontal axis drawn parallel to the central axis of the pipe. The presence of the generally planar lower compression region prevents the vertical lip portion from bending backward under pressure loading and wherein the angles .alpha. and .beta.