diff --git a/pandas/io/tests/test_parsers.py b/pandas/io/tests/test_parsers.py
index 93a26b70a019e..7f3b9ecb2ca5b 100644
--- a/pandas/io/tests/test_parsers.py
+++ b/pandas/io/tests/test_parsers.py
@@ -2037,16 +2037,16 @@ def test_usecols(self):
 4,5,6
 7,8,9
 10,11,12"""
-        result = self.read_csv(StringIO(data), names=['b', 'c'],
-                               header=None, usecols=[1, 2])
+        result = self.read_csv(StringIO(data), names=['a', 'b'],
+                               header=None, usecols=[0, 1])
 
         expected = self.read_csv(StringIO(data), names=['a', 'b', 'c'],
                                  header=None)
-        expected = expected[['b', 'c']]
+        expected = expected[['a', 'b']]
         tm.assert_frame_equal(result, expected)
 
         result2 = self.read_csv(StringIO(data), names=['a', 'b', 'c'],
-                                header=None, usecols=['b', 'c'])
+                                header=None, usecols=['a', 'b'])
         tm.assert_frame_equal(result2, result)
 
         # length conflict, passed names and usecols disagree
@@ -2072,7 +2072,6 @@ def test_catch_too_many_names(self):
 10,11,12\n"""
         tm.assertRaises(Exception, read_csv, StringIO(data), header=0, names=['a', 'b', 'c', 'd'])
 
-
 class TestPythonParser(ParserTests, tm.TestCase):
     def test_negative_skipfooter_raises(self):
         text = """#foo,a,b,c
diff --git a/pandas/parser.pyx b/pandas/parser.pyx
index 36b4b91023a73..4a93499f880c9 100644
--- a/pandas/parser.pyx
+++ b/pandas/parser.pyx
@@ -1135,8 +1135,11 @@ cdef class TextReader:
 
     cdef _get_column_name(self, Py_ssize_t i, Py_ssize_t nused):
         if self.has_usecols and self.names is not None:
-            if len(self.names) == len(self.usecols):
+            if len(self.names) == len(self.usecols) and nused < len(self.names):
                 return self.names[nused]
+            # addresses Issue #5766
+            elif nused >= len(self.names):
+                return None
             else:
                 return self.names[i - self.leading_cols]
         else: