diff --git a/lib/rdoc/options.rb b/lib/rdoc/options.rb
index 801a84b21f..53cc3af63c 100644
--- a/lib/rdoc/options.rb
+++ b/lib/rdoc/options.rb
@@ -344,7 +344,10 @@ def initialize # :nodoc:
 
   def init_ivars # :nodoc:
     @dry_run = false
-    @exclude = []
+    @exclude = %w[
+      ~\z \.orig\z \.rej\z \.bak\z
+      \.gemspec\z
+    ]
     @files = nil
     @force_output = false
     @force_update = true
diff --git a/test/test_rdoc_options.rb b/test/test_rdoc_options.rb
index baef2d860e..b6769d14b3 100644
--- a/test/test_rdoc_options.rb
+++ b/test/test_rdoc_options.rb
@@ -66,7 +66,7 @@ class << coder; alias add []=; end
     expected = {
       'charset'              => 'UTF-8',
       'encoding'             => encoding,
-      'exclude'              => [],
+      'exclude'              => %w[~\z \.orig\z \.rej\z \.bak\z \.gemspec\z],
       'hyperlink_all'        => false,
       'line_numbers'         => false,
       'locale'               => nil,