diff --git a/ibis/backends/sql/datatypes.py b/ibis/backends/sql/datatypes.py
index dd4a8acff8e75..dd3780b84a1cb 100644
--- a/ibis/backends/sql/datatypes.py
+++ b/ibis/backends/sql/datatypes.py
@@ -169,7 +169,9 @@ def to_ibis(cls, typ: sge.DataType, nullable: bool | None = None) -> dt.DataType
             )
             typecode = typ.this
 
-        nullable = typ.args.get("nullable", cls.default_nullable)
+        nullable = typ.args.get(
+            "nullable", nullable if nullable is not None else cls.default_nullable
+        )
         if method := getattr(cls, f"_from_sqlglot_{typecode.name}", None):
             dtype = method(*typ.expressions, nullable=nullable)
         elif (known_typ := _from_sqlglot_types.get(typecode)) is not None: