A seal arrangement for a gas turbine engine comprises a seal support having a hub portion and a peripheral rim portion. A seal member is mounted to a radially inner surface of the hub portion. A first set of circumferentially spaced-apart channel segments project from the peripheral rim portion of the seal support. A second set of circumferentially spaced-apart channel segments projects from a mating stationary structure of the gas turbine engine. The first and second sets of circumferentially spaced-apart channel segments circumferentially may be aligned to complementary form a circumferentially extending channel. A retaining ring may be mounted in the circumferentially extending channel for retaining the seal support on the mating stationary structure of the engine. The seal support may be provided with a diaphragm to provide flexibly between the seal member and the point of attachment of the seal support to the mating structure of the engine.