diff --git a/f90nml/parser.py b/f90nml/parser.py
index 29caf56..0523e4f 100644
--- a/f90nml/parser.py
+++ b/f90nml/parser.py
@@ -329,6 +329,9 @@ def _readstream(self, nml_file, nml_patch_in=None):
             except StopIteration:
                 break
 
+            # save whether & or $ is opening this group
+            opening_token = self.token
+
             # Create the next namelist
             try:
                 self._update_tokens()
@@ -384,6 +387,24 @@ def _readstream(self, nml_file, nml_patch_in=None):
                 # Finalise namelist group
                 if self.token in ('/', '&', '$'):
 
+                    if self.token in ('&', '$'):
+                        # Peek at the next non-whitespace token without
+                        # consuming it, to distinguish F77-style terminators
+                        # (&end or standalone &, or same with $) from
+                        # an unclosed group.
+                        self.tokens, peek_iter = itertools.tee(self.tokens)
+                        skip = self.comment_tokens + whitespace
+                        next_tok = next(
+                            (t for t in peek_iter if t[0] not in skip),
+                            None
+                        )
+                        if next_tok and next_tok.lower() not in ('end', '&', '$'):
+                            raise ValueError(
+                                "f90nml: error: Namelist group '{}{}' was not "
+                                "closed before the start of a new group or EOF."
+                                .format(opening_token, g_name)
+                            )
+
                     # Append any remaining patched variables
                     for v_name, v_val in grp_patch.items():
                         g_vars[v_name] = v_val
diff --git a/tests/end_uppercase.nml b/tests/end_uppercase.nml
new file mode 100644
index 0000000..572e841
--- /dev/null
+++ b/tests/end_uppercase.nml
@@ -0,0 +1,7 @@
+&END_TOKEN_UPPERCASE
+  a = 1
+&END
+
+&last_grp
+  a = 1
+&
\ No newline at end of file
diff --git a/tests/f77.nml b/tests/f77.nml
index d795759..af4f9e5 100644
--- a/tests/f77.nml
+++ b/tests/f77.nml
@@ -1,3 +1,7 @@
+$f77_nml_dollar
+    x = 123
+$end
+
 &f77_nml
     x = 123
 &end
@@ -5,3 +9,7 @@
 &next_f77_nml
     y = 'abc'
 &end
+
+&another_f77_nml
+    z = 99
+&
diff --git a/tests/f77_target.nml b/tests/f77_target.nml
index b7e90d7..ad946f6 100644
--- a/tests/f77_target.nml
+++ b/tests/f77_target.nml
@@ -1,3 +1,7 @@
+&f77_nml_dollar
+    x = 123
+/
+
 &f77_nml
     x = 123
 /
@@ -5,3 +9,7 @@
 &next_f77_nml
     y = 'abc'
 /
+
+&another_f77_nml
+    z = 99
+/
diff --git a/tests/first_grp_no_end.nml b/tests/first_grp_no_end.nml
new file mode 100644
index 0000000..55c9adf
--- /dev/null
+++ b/tests/first_grp_no_end.nml
@@ -0,0 +1,6 @@
+&open_group
+a = 1
+
+&closed_group
+b = 2
+/
diff --git a/tests/first_grp_no_end_dollar.nml b/tests/first_grp_no_end_dollar.nml
new file mode 100644
index 0000000..32939d0
--- /dev/null
+++ b/tests/first_grp_no_end_dollar.nml
@@ -0,0 +1,7 @@
+$open_group
+a = 1
+
+
+$closed_group
+b = 2
+$end
diff --git a/tests/test_f90nml.py b/tests/test_f90nml.py
index 96cc991..6835971 100644
--- a/tests/test_f90nml.py
+++ b/tests/test_f90nml.py
@@ -427,8 +427,10 @@ def setUp(self):
         }
 
         self.f77_nml = {
+            'f77_nml_dollar': {'x': 123},
             'f77_nml': {'x': 123},
             'next_f77_nml': {'y': 'abc'},
+            'another_f77_nml': {'z': 99},
         }
 
         self.dollar_nml = {'dollar_nml': {'v': 1.}}
@@ -1595,6 +1597,11 @@ def test_repeat_repeating_logical(self):
         line2 = out.readline()
         self.assertEqual(line2.lstrip(), "b = 2*.true., .false.\n")
 
+    def test_end_uppercase(self):
+        test_nml = f90nml.read('end_uppercase.nml')
+        self.assertEqual(test_nml, {'end_token_uppercase': {'a': 1},
+                                    'last_grp': {'a': 1}})
+
     # Failed namelist parsing
     # NOTE: This is a very weak test, since '& x=1' / will pass
     def test_grp_token_end(self):
@@ -1612,6 +1619,12 @@ def test_string_grp_no_end(self):
     def test_file_grp_no_end(self):
         self.assertRaises(ValueError, f90nml.read, 'grp_no_end.nml')
 
+    def test_file_first_grp_no_end(self):
+        self.assertRaises(ValueError, f90nml.read, 'first_grp_no_end.nml')
+
+    def test_file_first_grp_no_end_dollar(self):
+        self.assertRaises(ValueError, f90nml.read, 'first_grp_no_end_dollar.nml')
+
 
 if __name__ == '__main__':
     if os.path.isfile('tmp.nml'):