A non-spill drinking cup valve system (10) comprises a lid assembly (12) and a flexible valve member (14). The flexible valve member (14) is removably attachable to the lid assembly (12). The lid assembly (12) comprises a spout (16) having a drinking aperture (18) therein. The flexible valve member (14) comprises a protruding member (26) having a tip (52) and a drinking valve element (28) in the tip (52), which, in use, controls fluid flow into the spout (16) and out of the drinking aperture (18). The protruding member (26) and the spout (16) are of a complementary shape and, when the lid assembly (12) and the flexible valve member (14) are attached together, the protruding member (26) extends substantially into the spout (16).