A pipe coupling device includes a body adapted for insertion into a pipe, the body having a through passage, and on its outer surface a groove for receiving a seal for forming a fluid-tight seal between the pipe and the body, the seal having a retaining portion and a sealing portion, wherein either the groove, the seal or both are constructed and arranged such that the retaining portion holds the seal within the groove when the sealing portion is subjected to the insertion force experienced when the pipe coupling device is inserted into a pipe. Further, the base portion may be axially wider than the sealing portion. Further, the seal may include reinforcing means adapted to prevent the seal leaving the groove.