diff --git a/notebook/notebookapp.py b/notebook/notebookapp.py
index 8b8facceb..9946f6e90 100644
--- a/notebook/notebookapp.py
+++ b/notebook/notebookapp.py
@@ -754,15 +754,19 @@ class NotebookApp(JupyterApp):
         else:
             return py3compat.getcwd()
 
+    def _notebook_dir_validate(self, value, trait):
+        # Strip any trailing slashes
+        value = value.rstrip(os.sep)
+
+        if not os.path.isabs(value):
+            # If we receive a non-absolute path, make it absolute.
+            value = os.path.abspath(value)
+        if not os.path.isdir(value):
+            raise TraitError("No such notebook dir: %r" % value)
+        return value
+
     def _notebook_dir_changed(self, name, old, new):
         """Do a bit of validation of the notebook dir."""
-        if not os.path.isabs(new):
-            # If we receive a non-absolute path, make it absolute.
-            self.notebook_dir = os.path.abspath(new)
-            return
-        if not os.path.isdir(new):
-            raise TraitError("No such notebook dir: %r" % new)
-        
         # setting App.notebook_dir implies setting notebook and kernel dirs as well
         self.config.FileContentsManager.root_dir = new
         self.config.MappingKernelManager.root_dir = new
diff --git a/notebook/tests/test_notebookapp.py b/notebook/tests/test_notebookapp.py
index 4119d0858..daf4c4654 100644
--- a/notebook/tests/test_notebookapp.py
+++ b/notebook/tests/test_notebookapp.py
@@ -62,6 +62,11 @@ def test_invalid_nb_dir():
         with nt.assert_raises(TraitError):
             app.notebook_dir = tf
 
+def test_nb_dir_with_slash():
+    with TemporaryDirectory(suffix="_slash/") as td:
+        app = NotebookApp(notebook_dir=td)
+        nt.assert_false(app.notebook_dir.endswith("/"))
+
 def test_generate_config():
     with TemporaryDirectory() as td:
         app = NotebookApp(config_dir=td)
@@ -69,4 +74,4 @@ def test_generate_config():
         with nt.assert_raises(NoStart):
             app.start()
         assert os.path.exists(os.path.join(td, 'jupyter_notebook_config.py'))
-    
\ No newline at end of file
+