diff --git a/sphinx/ext/napoleon/docstring.py b/sphinx/ext/napoleon/docstring.py
index 4b8b6683e..4902c3099 100644
--- a/sphinx/ext/napoleon/docstring.py
+++ b/sphinx/ext/napoleon/docstring.py
@@ -292,7 +292,7 @@ class GoogleDocstring(UnicodeMixin):
             result_lines = []
             for i, line in enumerate(lines):
                 if i == 0:
-                    result_lines.append(prefix + line)
+                    result_lines.append((prefix + line).rstrip())
                 elif line:
                     result_lines.append(padding + line)
                 else:
diff --git a/tests/test_ext_napoleon_docstring.py b/tests/test_ext_napoleon_docstring.py
index 7b316ef97..853e73624 100644
--- a/tests/test_ext_napoleon_docstring.py
+++ b/tests/test_ext_napoleon_docstring.py
@@ -362,7 +362,7 @@ param1 : :class:`MyClass <name.space.MyClass>` instance
         config = Config(napoleon_use_param=True)
         actual = str(NumpyDocstring(docstring, config))
         expected = """\
-
+:param param1:
 :type param1: :class:`MyClass <name.space.MyClass>` instance
 """
         self.assertEqual(expected, actual)
@@ -385,7 +385,7 @@ param1 : MyClass instance
         config = Config(napoleon_use_param=True)
         actual = str(NumpyDocstring(textwrap.dedent(docstring), config))
         expected = """\
-
+:param param1:
 :type param1: MyClass instance
 """
         self.assertEqual(expected, actual)