Leviathan III is the nineteenth studio album by Swedish symphonic metal band Therion.

[1] It is the final part of the Leviathan trilogy of the band.

Band leader Christofer Johnsson stated that this closure of the Leviathan trilogy would compile the most "experimental and adventurous" songs from that songwriting period.

[2] The third part of the Leviathan Trilogy focuses on the apocalyptic themes, odes to the rulers of the underworld as well as on the mystical rituals of several mythologies and traditions from around the world.

AllMusic commended the album for being "ambitious", and said that, while the album was somewhat hard to grasp, repeated listens to it were "rewarding", as Leviathan III was "easily one of Therion's most diverse, dramatic, and dynamic recordings yet".