A cyclone separator assembly comprises at least one cyclone casing defining a cyclone chamber. The cyclone casing comprises a fluid inlet, a separated material outlet, and a fluid outlet. A separated material chamber is in communication with the separated material outlet. The cyclone chamber is openable by movement of a first movable portion, and the separated material chamber is openable by movement of a second movable portion separate from the first movable portion. A surface cleaning apparatus utilizing this construction is also provided. This construction is particularly useable if the separated material chamber is aligned with and below the cyclone chamber. Accordingly, the cyclone chamber and the separated material chamber may be sequentially or concurrently opened.