diff --git a/cmake/FindDocBookXML4.cmake b/cmake/FindDocBookXML4.cmake
--- a/cmake/FindDocBookXML4.cmake
+++ b/cmake/FindDocBookXML4.cmake
@@ -55,6 +55,8 @@
         ${CMAKE_INSTALL_DATAROOTDIR}/xml/docbook/xml-dtd-${version}
         ${CMAKE_INSTALL_DATAROOTDIR}/sgml/docbook/xml-dtd-${version}
         ${CMAKE_INSTALL_DATAROOTDIR}/xml/docbook/${version}
+        #for building on Mac with docbook installed by homebrew
+        opt/docbook/docbook/xml/${version}
     )
 
     find_path (searched_dir docbookx.dtd
diff --git a/cmake/FindDocBookXSL.cmake b/cmake/FindDocBookXSL.cmake
--- a/cmake/FindDocBookXSL.cmake
+++ b/cmake/FindDocBookXSL.cmake
@@ -44,6 +44,8 @@
     ${CMAKE_INSTALL_DATAROOTDIR}/xml/docbook/stylesheet/nwalsh
     ${CMAKE_INSTALL_DATAROOTDIR}/xsl/docbook
     ${CMAKE_INSTALL_DATAROOTDIR}/xsl/docbook-xsl
+    #for building on Mac with docbook-xsl installed by homebrew
+    opt/docbook-xsl/docbook-xsl
 )
 
 find_path (DocBookXSL_DIR lib/lib.xsl