  We analysed the clustering of a photometric sample of galaxy clusters
selected from the Third Data Release of the Kilo-Degree Survey, focusing on the
redshift-space two-point correlation function (2PCF). We compared our
measurements to theoretical predictions of the standard $\Lambda$ cold dark
matter ($\Lambda$CDM) cosmological model. We measured the 2PCF of the sample in
the cluster centric radial range $r\in[5,80]$ $h^{-1}$Mpc, considering 4934
galaxy clusters with richness $\lambda^*\geq15$ in the redshift range
$z\in[0.1,0.6]$. A Markov chain Monte Carlo analysis has been performed to
constrain the cosmological parameters $\Omega_{\rm m}$, $\sigma_8$, and $S_8
\equiv \sigma_8(\Omega_{\rm m}/0.3)^{0.5}$, assuming Gaussian priors on the
mass-richness relation given by the posteriors obtained from a joint analysis
of cluster counts and weak lensing. In addition, we constrained the
normalisation of the mass-richness relation, $\alpha$, with fixed cosmological
parameters. We obtained $\Omega_{\rm m}=0.28^{+0.05}_{-0.04}$,
$\sigma_8=0.82^{+0.14}_{-0.12}$, and $S_8=0.80^{+0.08}_{-0.08}$. The constraint
on $S_8$ is consistent within 1$\sigma$ with the results from WMAP and Planck.
Furthermore, by fixing the cosmological parameters to those provided by Planck,
we obtained $\alpha=0.12^{+0.06}_{-0.06}$, which is fully consistent with the
result obtained from the joint analysis of cluster counts and weak lensing
performed for this sample.
