diff --git a/discord/ext/commands/core.py b/discord/ext/commands/core.py
index 5809a156d..642fbe0f7 100644
--- a/discord/ext/commands/core.py
+++ b/discord/ext/commands/core.py
@@ -559,6 +559,8 @@ class Command(_BaseCommand):
             if required:
                 if self._is_typing_optional(param.annotation):
                     return None
+                if hasattr(converter, '__commands_is_flag__') and converter._can_be_constructible():
+                    return await converter._construct_default(ctx)
                 raise MissingRequiredArgument(param)
             return param.default
 
diff --git a/discord/ext/commands/flags.py b/discord/ext/commands/flags.py
index dc6327213..08f77d93f 100644
--- a/discord/ext/commands/flags.py
+++ b/discord/ext/commands/flags.py
@@ -408,6 +408,22 @@ class FlagConverter(metaclass=FlagsMeta):
         """Dict[:class:`str`, :class:`Flag`]: A mapping of flag name to flag object this converter has."""
         return cls.__commands_flags__.copy()
 
+    @classmethod
+    def _can_be_constructible(cls) -> bool:
+        return all(not flag.required for flag in cls.__commands_flags__.values())
+
+    @classmethod
+    async def _construct_default(cls: Type[F], ctx: Context) -> F:
+        self: F = cls.__new__(cls)
+        flags = cls.__commands_flags__
+        for flag in flags.values():
+            if callable(flag.default):
+                default = await maybe_coroutine(flag.default, ctx)
+                setattr(self, flag.attribute, default)
+            else:
+                setattr(self, flag.attribute, flag.default)
+        return self
+
     def __repr__(self) -> str:
         pairs = ' '.join([f'{flag.attribute}={getattr(self, flag.attribute)!r}' for flag in self.get_flags().values()])
         return f'<{self.__class__.__name__} {pairs}>'