To Mega Therion is the second studio album[note 1] by Swiss extreme metal band Celtic Frost, released in October 1985 through Noise Records.

It is an expression found in the Bible but was also a nickname used by Aleister Crowley Ned Raggett in his review for AllMusic wrote, "The bombastic 'Innocence and Wrath' starts To Mega Therion off on just the appropriate note – Wagnerian horn lines, booming drums, and a slow crunch toward apocalypse. ...

With that setting the tone, it is into the maddeningly wild and woolly Celtic Frost universe full bore, Warrior roaring out his vocals with glee and a wicked smile while never resorting to self-parodic castrato wails.

According to Raggett, "other prime cuts" include "Circle of the Tyrants", "Dawn of Megiddo", "Tears in a Prophet's Dream", "Eternal Summer" and "Necromantical Screams".

He remarks how "the band had decided to delve more into the extreme" and praised Tom Warrior's "surprisingly accomplished" lyrics and the mix of death, black and doom metal with a pinch of ambient music.