diff --git a/README.md b/README.md
index b6d6c0dd2..fe13e710e 100644
--- a/README.md
+++ b/README.md
@@ -357,6 +357,30 @@ Unacceptable input example:
 C:/whatever
 ```
 
+#### `Stdlib::Filemode`
+
+Matches valid four digit modes in octal format.
+
+Acceptable input examples:
+
+```shell
+0644
+```
+
+```shell
+1777
+```
+
+Unacceptable input examples:
+
+```shell
+644
+```
+
+```shell
+0999
+```
+
 #### `Stdlib::Windowspath`
 
 Matches paths on Windows operating systems.
diff --git a/spec/aliases/filemode_spec.rb b/spec/aliases/filemode_spec.rb
new file mode 100644
index 000000000..4db13a20e
--- /dev/null
+++ b/spec/aliases/filemode_spec.rb
@@ -0,0 +1,48 @@
+require 'spec_helper'
+
+if Puppet::Util::Package.versioncmp(Puppet.version, '4.5.0') >= 0
+  describe 'test::filemode', type: :class do
+    describe 'valid modes' do
+      %w{
+        0644
+        1644
+        2644
+        4644
+        0123
+        0777
+      }.each do |value|
+        describe value.inspect do
+          let(:params) {{ value: value }}
+          it { is_expected.to compile }
+        end
+      end
+    end
+
+    describe 'invalid modes' do
+      context 'garbage inputs' do
+        [
+          nil,
+          [ nil ],
+          [ nil, nil ],
+          { 'foo' => 'bar' },
+          { },
+          '',
+          "ネット",
+          '644',
+          '7777',
+          '1',
+          '22',
+          '333',
+          '55555',
+          '0x123',
+          '0649',
+        ].each do |value|
+          describe value.inspect do
+            let(:params) {{ value: value }}
+            it { is_expected.to compile.and_raise_error(/parameter 'value' expects a match for Stdlib::Filemode/) }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/fixtures/test/manifests/filemode.pp b/spec/fixtures/test/manifests/filemode.pp
new file mode 100644
index 000000000..56864072d
--- /dev/null
+++ b/spec/fixtures/test/manifests/filemode.pp
@@ -0,0 +1,6 @@
+# Class to test the Stdlib::Filemode type alias
+class test::filemode (
+  Stdlib::Filemode $value,
+) {
+  notice("Success")
+}
diff --git a/types/filemode.pp b/types/filemode.pp
new file mode 100644
index 000000000..ed45ff7fc
--- /dev/null
+++ b/types/filemode.pp
@@ -0,0 +1 @@
+type Stdlib::Filemode = Pattern[/^[0124]{1}[0-7]{3}$/]