  We compute the electric dipole moment (EDM) of the deuteron in the
holographic QCD model of Witten-Sakai-Sugimoto. Previously, the leading
contribution to the EDM of nucleons was computed, finding opposite values for
the proton and the neutron which then cancel each other in the deuteron state.
Here we compute the next-to-leading order contribution which provides a
splitting between their absolute value. At large $N_{\rm c}$ and large 't Hooft
coupling $\lambda$, nuclei are bound states of almost isolated nucleons. In
particular, we find that in this limit the deuteron EDM is given by the
splitting between proton and neutron EDMs. Our estimate for the deuteron EDM
extrapolated to the physical values of $N_{\rm c}$, $\lambda$, $M_{\rm KK}$ and
$m_q$ is $\mathcal{D}_D = -0.92\times 10^{-16} \theta\ e \cdot {cm}$. This is
consistent, in sign and magnitude, with results found previously in the
literature and obtained using completely different methods.
