Methanomicrobiales is an order of archaeans in the phylum Methanobacteriota. Methanomicrobiales are strictly carbon dioxide reducing methanogens, using hydrogen or formate as the reducing agent. As seen from the phylogenetic tree based on 'The All-Species Living Tree' Project the family Methanomicrobiaceae is highly polyphyletic within the Methanomicrobiales.
The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI).