diff --git a/mashumaro/jsonschema/plugins.py b/mashumaro/jsonschema/plugins.py
index 0974d07..3396c9c 100644
--- a/mashumaro/jsonschema/plugins.py
+++ b/mashumaro/jsonschema/plugins.py
@@ -1,4 +1,5 @@
 from dataclasses import is_dataclass
+from inspect import cleandoc
 from typing import Optional
 
 from mashumaro.jsonschema.models import Context, JSONSchema
@@ -23,5 +24,5 @@ def get_schema(
         schema: Optional[JSONSchema] = None,
     ) -> Optional[JSONSchema]:
         if schema and is_dataclass(instance.type) and instance.type.__doc__:
-            schema.description = instance.type.__doc__
+            schema.description = cleandoc(instance.type.__doc__)
         return None