Botryotinia is a genus of ascomycete fungi causing several plant diseases.

The anamorphs of Botryotinia are mostly included in the "imperfect fungi" genus Botrytis.

The fungi induce host cell death resulting in progressive decay of infected plant tissue, whence they take nutrients.

Some species also cause damping off, killing seeds or seedlings during or before germination.

Botryotinia fuckeliana (or its anamorph Botrytis cinerea) is an important species for wine industry as well as horticulture.