  Axion-like particles (ALPs) provide a promising direction in the search for
new physics, while a wide range of models incorporate ALPs. We point out that
future neutrino experiments, such as DUNE, possess competitive sensitivity to
ALP signals. The high-intensity proton beam impinging on a target can not only
produce copious amounts of neutrinos, but also cascade photons that are created
from charged particle showers stopping in the target. Therefore, ALPs
interacting with photons can be produced (often energetically) with high
intensity via the Primakoff effect and then leave their signatures at the near
detector through the inverse Primakoff scattering or decays to a photon pair.
Moreover, the high-capability near detectors allow for discrimination between
ALP signals and potential backgrounds, improving the signal sensitivity
further. We demonstrate that a DUNE-like detector can explore a wide range of
parameter space in ALP-photon coupling $g_{a\gamma}$ vs ALP mass $m_a$,
including some regions unconstrained by existing bounds; the "cosmological
triangle" will be fully explored and the sensitivity limits would reach up to
$m_a\sim3-4$ GeV and down to $g_{a\gamma}\sim 10^{-8} {\rm GeV}^{-1}$.

High Energy Physics - Phenomenology;High Energy Physics - Experiment