Mutual phase locking of Josephson junctions in a multijunction superconducting loop (MSL) was investigated both theoretically and experimentally. The theoretical analysis predicts the existence of phase‐locked states, where the circulating current in the loop serves for phase locking between junctions. The basic operating principles of a MSL were studied experimentally using high‐TCbicrystal Josephson junctions. The enhancement of phase locking stability with respect to series arrays is reported. ©1995 American Institute of Physics.