diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,6 +57,9 @@
                        PURPOSE "Required by the KDE help system to process DocBook XML"
                       )
 
+if (NOT LIBXML2_XMLLINT_EXECUTABLE)
+   message(FATAL_ERROR "xmllint is required to process DocBook XML")
+endif()
 
 find_package(DocBookXML4 "4.5")