The Wallabies fullback Folau has been found guilty by Rugby Australia of committing a high-level breach of their code of conduct.
The decision comes after a three-day hearing on whether his social media post that said hell awaited "drunks, homosexuals, adulterers" and others, was a breach of its rules.
A panel is now considering sanctions.
England number eight Billy Vunipola and Queensland Reds captain Samu Kerevi were among several Pasifika athletes to "like" Folau's original post on Instagram.