A printing liquid container fits to one of first and second tanks each including a fitted portion. The printing liquid container includes a first member having a supply port, and a second member having a valve configured to open or close the supply port. The first member and the second member are rotatable with respect to each other between a first state and a second state. The valve closes the supply port in the first state and opens the supply port in the second state. The first member has a fitting portion configured to fit to the fitted portion. The second member is rotatable with respect to the fitted portion when at least a portion of the second member is inserted into the fitted portion. The first member does not rotate by the rotation of the second member due to the fitting between the fitted portion and the fitting portion.