diff --git a/singer/transform.py b/singer/transform.py
index 3a9fc96..b9fabba 100644
--- a/singer/transform.py
+++ b/singer/transform.py
@@ -331,6 +331,12 @@ def _transform(self, data, typ, schema, path):
                 return False, None
 
         elif typ == "boolean":
+            # None and "" must fall through to the null handler; bool(None)
+            # and bool("") both return False without raising, which would
+            # silently coerce null values to false for ["null", "boolean"] schemas.
+            if data is None or data == "":
+                return False, None
+
             if isinstance(data, str) and data.lower() == "false":
                 return True, False