diff --git a/tailbone/grids/core.py b/tailbone/grids/core.py
index 63ea83bd..4f79587b 100644
--- a/tailbone/grids/core.py
+++ b/tailbone/grids/core.py
@@ -115,7 +115,10 @@ class Grid(object):
             self.columns.remove(key)
 
     def set_joiner(self, key, joiner):
-        self.joiners[key] = joiner
+        if joiner is None:
+            self.joiners.pop(key, None)
+        else:
+            self.joiners[key] = joiner
 
     def set_sorter(self, key, *args, **kwargs):
         self.sorters[key] = self.make_sorter(*args, **kwargs)