A reference electrode assembly for an electrochemical sensor, in particular for a potentiometric sensor, comprising a reference half-cell space having a reference electrode provided therein, the reference half-space comprising a storage space in which a reference electrolyte is provided at any rate in a storage state of the reference electrode assembly, the reference half-cell space further comprising a lock space that is permeable at any rate with respect to the passage of reference electrolyte into an environment of the reference half-cell space, the storage space, in the storage state of the reference electrode assembly, being separated from the lock space with respect to the passage of reference electrolyte, the reference electrode assembly being designed such that a connection permeable for the passage of reference electrolyte from the storage space to the lock space can be created between the storage space and the lock space in order to transfer the reference electrode assembly from the storage state to an operative state.