  Both gamma-ray bursts (GRBs) and blazars have relativistic jets pointing at a
small angle from our line of sight. Several recent studies suggested that these
two kinds of sources may share similar jet physics. In this work, we explore
the variability properties for GRBs and blazars as a whole. We find that the
correlation between minimum variability timescale (MTS) and Lorentz factor,
$\Gamma$, as found only in GRBs by Sonbas et al. can be extended to blazars
with a joint correlation of $\rm MTS\propto\Gamma^{-4.7\pm0.3}$. The same
applies to the $\rm MTS\propto \it L_{\gamma}^{\rm -1.0\pm0.1}$ correlation as
found in GRBs, which can be well extended into blazars as well. These results
provide further evidence that the jets in these two kinds of sources are
similar despite of the very different mass scale of their central engines.
Further investigations of the physical origin of these correlations are needed,
which can shed light on the nature of the jet physics.
