diff --git a/lib/puppet/parser/functions/ensure_prefix.rb b/lib/puppet/parser/functions/ensure_prefix.rb
new file mode 100644
index 00000000..631f2704
--- /dev/null
+++ b/lib/puppet/parser/functions/ensure_prefix.rb
@@ -0,0 +1,56 @@
+
+module Puppet::Parser::Functions
+  newfunction(:ensure_prefix, :type => :rvalue, :doc => <<-EOS
+This function ensures a prefix for all elements in an array or the keys in a hash.
+
+*Examples:*
+
+  ensure_prefix({'a' => 1, 'b' => 2, 'p.c' => 3}, 'p.')
+
+Will return:
+  {
+    'p.a' => 1,
+    'p.b' => 2,
+    'p.c' => 3,
+  }
+
+  ensure_prefix(['a', 'p.b', 'c'], 'p.')
+
+Will return:
+  ['p.a', 'p.b', 'p.c']
+EOS
+  ) do |arguments|
+
+    raise(Puppet::ParseError, "ensure_prefix(): Wrong number of arguments " +
+      "given (#{arguments.size} for 2)") if arguments.size < 2
+
+    enumerable = arguments[0]
+
+    unless enumerable.is_a?(Array) or enumerable.is_a?(Hash)
+      raise Puppet::ParseError, "ensure_prefix(): expected first argument to be an Array or a Hash, got #{enumerable.inspect}"
+    end
+
+    prefix = arguments[1] if arguments[1]
+
+    if prefix
+      unless prefix.is_a?(String)
+        raise Puppet::ParseError, "ensure_prefix(): expected second argument to be a String, got #{prefix.inspect}"
+      end
+    end
+
+    if enumerable.is_a?(Array)
+      # Turn everything into string same as join would do ...
+      result = enumerable.collect do |i|
+        i = i.to_s
+        prefix && !i.start_with?(prefix) ? prefix + i : i
+      end
+    else
+      result = Hash[enumerable.map do |k,v|
+        k = k.to_s
+        [ prefix && !k.start_with?(prefix) ? prefix + k : k, v ]
+      end]
+    end
+
+    return result
+  end
+end
diff --git a/manifests/extension.pp b/manifests/extension.pp
index 1a86dece..8032b55c 100644
--- a/manifests/extension.pp
+++ b/manifests/extension.pp
@@ -33,6 +33,10 @@
 # [*settings*]
 #   Nested hash of global config parameters for php.ini
 #
+# [*settings_prefix*]
+#  Boolean parameter, whether to prefix all setting keys with
+#  the extension name. Defaults to true.
+#
 define php::extension(
   $ensure            = 'installed',
   $provider          = undef,
@@ -43,6 +47,7 @@
   $compiler_packages = $::php::params::compiler_packages,
   $zend              = false,
   $settings          = {},
+  $settings_prefix   = true,
 ) {
 
   if $caller_module_name != $module_name {
@@ -110,23 +115,36 @@
 
   $lowercase_title = downcase($title)
 
+  # Ensure "<extension>." prefix is present in setting keys if requested
+  if $settings_prefix {
+    $full_settings = ensure_prefix($settings, "${name}.")
+  } else {
+    $full_settings = $settings
+  }
+
   if $provider == 'pecl' {
-    $real_settings = deep_merge({"${extension_key}"=>"${name}.so"},$settings)
+    $final_settings = deep_merge(
+      {"${extension_key}" => "${name}.so"},
+      $full_settings
+    )
   }
   else {
     # On FreeBSD systems the settings file is required for every module
     # (regardless of provider) to allow for proper module management.
     if $::osfamily == 'FreeBSD' {
-      $real_settings = deep_merge({"${extension_key}"=>"${name}.so"},$settings)
+      $final_settings = deep_merge(
+        {"${extension_key}" => "${name}.so"},
+        $full_settings
+      )
     }
     else {
-      $real_settings = $settings
+      $final_settings = $full_settings
     }
   }
 
   ::php::config { $title:
     file   => "${::php::params::config_root_ini}/${lowercase_title}.ini",
-    config => $real_settings,
+    config => $final_settings,
   }
 
   # Ubuntu/Debian systems use the mods-available folder. We need to enable
diff --git a/spec/defines/extension_spec.rb b/spec/defines/extension_spec.rb
index 7722fd5b..2c8a0ed0 100644
--- a/spec/defines/extension_spec.rb
+++ b/spec/defines/extension_spec.rb
@@ -19,7 +19,7 @@
       should contain_php__config('json').with({
         :file   => '/etc/php5/mods-available/json.ini',
         :config => {
-          'test' => 'foo'
+          'json.test' => 'foo'
         },
       })
     }
@@ -53,7 +53,7 @@
         :file   => '/etc/php5/mods-available/json.ini',
         :config => {
           'extension' => 'nice_name.so',
-          'test'      => 'foo'
+          'nice_name.test'      => 'foo'
         },
       })
     }