Strain rate sensitivity (SRS) of CuZr-based bulk metallic glass composites (BMGCs) containing a B2-CuZr phase with different volume fractions were investigated by performing uniaxial compression tests in a strain-rate-jump mode. It was found that the SRS exponents of the BMGCs could vary from negative to positive within the strain-rate range from 3.7×10?5 s?1 to 3.7×10?3 s?1 with increasing the B2-CuZr phase volume fraction. However, the positive SRS exponent of the BMGC with a higher B2-CuZr phase volume fraction of up to about 80% was still unexpectedly low. This was attributed to the limited strain-rate-dependence of mechanical behavior of the B2-CuZr phase, which was induced by the martensitic transformation effect of the phase during deformation. It appears that the SRS ceiling of the CuZr-based BMGCs is controlled by the B2-CuZr phase.