Climacocystis
{{Short description|Genus of fungi}}
{{Automatic taxobox
| image = Climacocystis borealis 38653.jpg
| image_caption = Climacocystis borealis
| taxon = Climacocystis
| authority = Kotl. & Pouzar (1958)
| type_species = Polyporus borealis
| type_species_authority = Fr. (1821)
| subdivision_ranks = Species
| subdivision = C. borealis
}}
Climacocystis is a genus of poroid fungi in the family Climacocystaceae.{{cite web |last1=Bensch |first1=K. |title=Climacocystis |url=https://www.mycobank.org/details/708/56309 |website=MycoBank |publisher= International Mycological Association and Westerdijk Fungal Biodiversity Institute |access-date=22 April 2025}} Until recently, it was monotypic genus, containing the single widespread species Climacocystis borealis. In 2014, Chinese mycologists added the newly described species Climacocystis montana. The generic name combines the name Climacodon with the Ancient Greek word {{lang|grc|χύστιζ}} ("bladder").