  We investigate the weak decays of the triply heavy baryon $\Omega_{QQQ}$ in
the light-front quark model. Since $\Omega_{QQQ}$ consists of three
indistinguishable identical heavy quarks, the commonly adopted quark-diquark
picture does not seem to be valid anymore. Instead, we employ the three-quark
picture for baryons where the three quarks are regarded as individual quarks.
We calculate the hadronic form factors for the transitions and give predictions
for the decay widths of the semi-leptonic decay modes $\Omega_{ccc}\to
\Xi_{cc}/ \Omega_{cc}+ l\bar{\nu}_l$, $\Omega_{bbb}\to \Xi _{bb}+ l
\bar{\nu}_l$ and the non-leptonic decay modes $\Omega_{ccc}\to
\Xi_{cc}/\Omega_{cc}+ M$, $\Omega_{bbb}\to \Xi_{bb}+ M$. Our study can be a
guide for future experiments to discover the triply heavy baryons.
