The exact analytic solutions of Maxwell equations for magnetic field exterior to a slowly rotating magnetized relativistic star in Einstein-aether gravity have been obtained. The obtained analytical expressions were used to derive Goldreich–Julian charge density in plasma magnetosphere and solutions of Poisson equation for the unscreened electric field being parallel to the magnetic field lines in the presence of the aether theory parameters were obtained. As astrophysical applications, we have explored the effects of Einstein-aether gravity on total energy losses of rotating magnetized relativistic star due to magnetodipolar and magnetospheric electromagnetic radiations. The performed study of deathline of radio pulsars through inverse Compton and curvature radiation shows that the position of deathline shifts up (down) in period and its derivative space, so-called P − P ̇ diagram in the presence of larger values of the Einstein-aether gravity parameter c 13 ( c 14 ). Finally, we have provided upper limits for Einstein-aether gravity parameters using observational data on precise measurements of periods of rotation from the different types of isolated neutron stars. In particular, we have shown that some combinations and range of the Einstein-aether are excluded from pulsar observations.