  This is the summary document of the virtual workshop "Opportunities of OO and
$p$O collisions at the LHC", which took place Feb 4-10, 2021. We briefly review
the presented perspectives on the physics opportunities of oxygen--oxygen and
proton--oxygen collisions. The full workshop program and the recordings are
available at cern.ch/OppOatLHC.

High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena;High Energy Physics - Experiment;Nuclear Experiment;Nuclear Theory