A lid for a beverage container having a reservoir chamber for holding drink additive, a measurement chamber in fluid communication with the measurement chamber, and an upper chamber with a lower end in fluid communication with an upper end portion of the reservoir chamber. A plunger has an upper chamber seal, an upper seal and a lower seal, and an actuator moves the plunger between first, second and third plunger positions to dispense a measured drink additive in the measurement chamber into the container. The plunger has a central filler port to receive drink additive and an aperture in fluid communication with the reservoir chamber. The actuator includes a closure member closing the filler port and manually movable to move the plunger. A lock member is movable between locked and unlocked positions, and in the locked position prevents movement of the plunger from the first to the second plunger position.