  In high energy hadron collisions, direct photons can be produced in various
processes and are of particular interest to study the hot QCD medium since they
escape it without being affected. In these proceedings are presented the latest
ALICE experiment results concerning direct photon production in proton-proton
(pp), proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions. All measurements
agree with pQCD calculations at high transverse momentum ($p_{\text{T}}$) and
show no direct photon excess at low $p_{\text{T}}$ in small systems while a low
$p_{\text{T}}$ signal is found in central Pb-Pb collisions.
