But it criticized the permanent nature of the ban as beyond the scope of Facebook’s normal penalties.
It has ordered Facebook to review the decision and justify a proportionate response that is applied to everyone, including ordinary users.
The former president was banned from both sites in January following the Capitol Hill riots.
The Oversight Board said the initial decision to permanently suspend Trump was indeterminate and standard-less and that the correct response should be consistent with the rules that are applied to other users of its platform.
It said Facebook must respond within six months,
