diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
index a6040e8a5f..b4b12bb959 100644
--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -404,6 +404,19 @@
     </para>
 </section>
 
+<section id='ref-classes-cmake'>
+    <title><filename>cmake.bbclass</filename></title>
+
+    <para>
+        The CMake build system (<filename>cmake</filename>) class allows for
+        recipes that need to build software using the CMake build system.
+        You can use the
+        <link linkend='var-EXTRA_OECMAKE'><filename>EXTRA_OECMAKE</filename></link>
+        variable to specify additional configuration options to be passed on
+        the <filename>cmake</filename> command line.
+    </para>
+</section>
+
 <section id='ref-classes-debian'>
     <title>Debian Renaming - <filename>debian.bbclass</filename></title>