  In this paper, we investigate the existence of bulk viscous FLRW cosmological
models in a recently proposed extended symmetric teleparallel gravity or
$f\left( Q,T\right) $ gravity in which $Q$ is the non-metricity and $T$ is the
trace of the energy-momentum tensor. We consider a simple coupling between
matter and non-metricity, specifically, $f\left( Q,T\right) =\alpha
Q^{m+1}+\lambda T$ and $f\left( Q,T\right) =\alpha Q+\lambda T$ where $\alpha
$, $\lambda $ and $m$ are free model parameters. The exact cosmological
solutions are found by assuming the scale factor in the form of the hybrid
expansion law. This type of relation generates a time-varying deceleration
parameter with the transition of the Universe from the early decelerating phase
to the present accelerating phase. In the presence of viscous fluid, we analyze
some cosmological parameters of our cosmological model such as the energy
density, bulk viscous pressure, bulk viscous coefficient, equation of state
parameter, and energy conditions. Finally, we conclude our $f\left( Q,T\right)
$\ cosmological models agree with the recent astronomical observations.
