A breast cup assembly for a breast pump has a generally funnel-shaped support member with an open wide end, an open narrow end, a tapered central passage extending between the wide end and the narrow end. A liner is positioned at least in part in the support member. The liner has a first noncircular opening therein for receiving at least a portion of a breast including a nipple, a second opening spaced from the first noncircular opening, and a tubular passageway between the first noncircular opening and the second opening for allowing milk expressed from the breast received in the liner to pass through the liner. The liner is configured for movement between an opened configuration of the noncircular opening and a collapsed configuration of the noncircular opening.