diff --git a/progit/hooks/__init__.py b/progit/hooks/__init__.py
index 69be6b0..e21b56b 100644
--- a/progit/hooks/__init__.py
+++ b/progit/hooks/__init__.py
@@ -20,17 +20,20 @@ class RequiredIf(wtforms.validators.Required):
         has a value.
         """
 
-        def __init__(self, other_field_name, *args, **kwargs):
-            self.other_field_name = other_field_name
+        def __init__(self, fields, *args, **kwargs):
+            if isinstance(fields, basestring):
+                fields = [fields]
+            self.fields = fields
             super(RequiredIf, self).__init__(*args, **kwargs)
 
         def __call__(self, form, field):
-            other_field = form._fields.get(self.other_field_name)
-            if other_field is None:
-                raise Exception(
-                    'no field named "%s" in form' % self.other_field_name)
-            if bool(other_field.data):
-                super(RequiredIf, self).__call__(form, field)
+            for fieldname in self.fields:
+                nfield = form._fields.get(fieldname)
+                if nfield is None:
+                    raise Exception(
+                        'no field named "%s" in form' % fieldname)
+                if bool(nfield.data):
+                    super(RequiredIf, self).__call__(form, field)
 
 
 class BaseHook(object):