We theoretically demonstrate the possibility to synchronize polarization chaos generated by a free-running vertical-cavity surface-emitting laser (VCSEL). We highlight two distinct synchronization regimes: 1) a high-quality synchronization regime where all polarization modes and total intensity are synchronized, which shows good robustness against parameter mismatch, and 2) a “slow time-scale” synchronization where the slower part of the dynamics—that is, the random-like hopping between the two scrolls of the chaotic attractor—synchronizes while the faster oscillations remain unsynchronized.