  This article presents the potential of a combined analysis of the JUNO and
KM3NeT/ORCA experiments to determine the neutrino mass ordering. This
combination is particularly interesting as it significantly boosts the
potential of either detector, beyond simply adding their neutrino mass ordering
sensitivities, by removing a degeneracy in the determination of $\Delta
m_{31}^2$ between the two experiments when assuming the wrong ordering. The
study is based on the latest projected performances for JUNO, and on simulation
tools using a full Monte Carlo approach to the KM3NeT/ORCA response with a
careful assessment of its energy systematics. From this analysis, a $5\sigma$
determination of the neutrino mass ordering is expected after 6 years of joint
data taking for any value of the oscillation parameters. This sensitivity would
be achieved after only 2 years of joint data taking assuming the current global
best-fit values for those parameters for normal ordering.
