diff --git a/autotests/CMakeLists.txt b/autotests/CMakeLists.txt
--- a/autotests/CMakeLists.txt
+++ b/autotests/CMakeLists.txt
@@ -1,3 +1,40 @@
+include(ECMMarkAsTest)
+
+find_package(Qt5 ${REQUIRED_QT_VERSION} CONFIG REQUIRED Core Test)
+
+find_package(LibXslt REQUIRED)
+find_package(LibXml2 REQUIRED)
+
+include_directories( ${LIBXML2_INCLUDE_DIR} ${LIBXSLT_INCLUDE_DIR} )
+
+include_directories(${CMAKE_CURRENT_BINARY_DIR}/../src)
+include_directories(${CMAKE_CURRENT_BINARY_DIR}/..)
+
+add_definitions(-DSIMPLE_XSLT)
+
+function(kdoctools_define_document_test basetest)
+  set(documentdirstest_SRCS
+    ${basetest}.cpp
+    ../src/xslt.cpp
+    ${CMAKE_CURRENT_BINARY_DIR}/../src/loggingcategory.cpp
+  )
+
+  add_executable(${basetest} ${documentdirstest_SRCS})
+  target_link_libraries(${basetest}
+    Qt5::Core Qt5::Test
+    ${LIBXML2_LIBRARIES} ${LIBXSLT_LIBRARIES} ${LIBXSLT_EXSLT_LIBRARIES}
+  )
+
+  add_test(NAME ${basetest} COMMAND ${basetest})
+  ecm_mark_as_test(${basetest})
+endfunction()
+
+kdoctools_define_document_test(documentdirstest)
+
+kdoctools_define_document_test(documentcustomdirtest)
+# custom path, used by the test
+target_compile_definitions(documentcustomdirtest PRIVATE KDOCTOOLS_CUSTOM_DOC_PATH="/usr/share/doc/kde/HTML")
+
 add_test(
   NAME meinproc_template
   COMMAND meinproc5 --srcdir ${CMAKE_CURRENT_BINARY_DIR}/../src ${CMAKE_CURRENT_SOURCE_DIR}/../src/template.docbook
diff --git a/autotests/documentcustomdirtest.cpp b/autotests/documentcustomdirtest.cpp
new file mode 100644
--- /dev/null
+++ b/autotests/documentcustomdirtest.cpp
@@ -0,0 +1,37 @@
+#include <QDebug>
+#include <QRegularExpression>
+#include <QTest>
+
+#include "../src/docbookxslt.h"
+#include "config-kdoctools.h"
+#include "loggingcategory.h"
+
+using namespace KDocTools;
+
+class documentCustomDirTest: public QObject
+{
+    Q_OBJECT
+private Q_SLOTS:
+    void testDirsContent();
+};
+
+void documentCustomDirTest::testDirsContent()
+{
+    const QStringList docDirs = documentationDirs();
+    QVERIFY(docDirs.size() >= 1);
+    /* DOCBUNDLEDIR (one of its matches) must be the first element */
+    QVERIFY(docDirs[0].indexOf(QRegularExpression(QStringLiteral(KDOCTOOLS_DOCBUNDLEDIR))) >= 0);
+    /* Check all the other items that should be there;
+       check the last occurrence, as each locateAll can return more items
+       and also some of them may match KDOCTOOLS_DOCBUNDLEDIR */
+    int position_dir_doc_HTML = docDirs.lastIndexOf(QRegularExpression(QStringLiteral(".*/doc/HTML$")));
+    QVERIFY(position_dir_doc_HTML >= 0);
+    int position_dir_help = docDirs.lastIndexOf(QRegularExpression(QStringLiteral(".*/help$")));
+    QVERIFY(position_dir_help >= 0);
+    /* The custom directory */
+    int position_dir_custom = docDirs.lastIndexOf(QStringLiteral(KDOCTOOLS_CUSTOM_DOC_PATH));
+    QVERIFY(position_dir_custom >= 0);
+}
+
+QTEST_MAIN(documentCustomDirTest)
+#include "documentcustomdirtest.moc"
diff --git a/autotests/documentdirstest.cpp b/autotests/documentdirstest.cpp
new file mode 100644
--- /dev/null
+++ b/autotests/documentdirstest.cpp
@@ -0,0 +1,34 @@
+#include <QDebug>
+#include <QRegularExpression>
+#include <QTest>
+
+#include "../src/docbookxslt.h"
+#include "config-kdoctools.h"
+#include "loggingcategory.h"
+
+using namespace KDocTools;
+
+class documentDirsTest: public QObject
+{
+    Q_OBJECT
+private Q_SLOTS:
+    void testDirsContent();
+};
+
+void documentDirsTest::testDirsContent()
+{
+    const QStringList docDirs = documentationDirs();
+    QVERIFY(docDirs.size() >= 1);
+    /* DOCBUNDLEDIR (one of its matches) must be the first element */
+    QVERIFY(docDirs[0].indexOf(QRegularExpression(QStringLiteral(KDOCTOOLS_DOCBUNDLEDIR))) >= 0);
+    /* Check all the other items that should be there;
+       check the last occurrence, as each locateAll can return more items
+       and also some of them may match KDOCTOOLS_DOCBUNDLEDIR */
+    int position_dir_doc_HTML = docDirs.lastIndexOf(QRegularExpression(QStringLiteral(".*/doc/HTML$")));
+    QVERIFY(position_dir_doc_HTML >= 0);
+    int position_dir_help = docDirs.lastIndexOf(QRegularExpression(QStringLiteral(".*/help$")));
+    QVERIFY(position_dir_help >= 0);
+}
+
+QTEST_MAIN(documentDirsTest)
+#include "documentdirstest.moc"
diff --git a/config-kdoctools.h.cmake b/config-kdoctools.h.cmake
--- a/config-kdoctools.h.cmake
+++ b/config-kdoctools.h.cmake
@@ -3,3 +3,13 @@
 #define DOCBOOK_XML_CURRDTD "@DocBookXML4_DTD_DIR@"
 
 #define KDOCTOOLS_INSTALL_DATADIR_KF5 "${CMAKE_INSTALL_PREFIX}/${KDE_INSTALL_DATADIR_KF5}"
+
+#define KDOCTOOLS_DOCBUNDLEDIR "${KDE_INSTALL_DOCBUNDLEDIR}"
+
+/* Get the value set in the library at compile time, or allow the application
+   to set it if the library has not defined it (useful for example for testing
+   purposes)
+*/
+#ifndef KDOCTOOLS_CUSTOM_DOC_PATH
+#define KDOCTOOLS_CUSTOM_DOC_PATH "${KDOCTOOLS_CUSTOM_DOC_PATH}"
+#endif
diff --git a/src/xslt.cpp b/src/xslt.cpp
--- a/src/xslt.cpp
+++ b/src/xslt.cpp
@@ -489,5 +489,13 @@
 QStringList KDocTools::documentationDirs()
 {
     /* List of paths containing documentation */
-    return QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("doc/HTML"), QStandardPaths::LocateDirectory);
+    QStringList allDocDirs;
+    allDocDirs << QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral(KDOCTOOLS_DOCBUNDLEDIR), QStandardPaths::LocateDirectory)
+               << QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("doc/HTML"), QStandardPaths::LocateDirectory)
+               << QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("help"), QStandardPaths::LocateDirectory);
+    if (!QStringLiteral(KDOCTOOLS_CUSTOM_DOC_PATH).isEmpty()) {
+        allDocDirs << QStringLiteral(KDOCTOOLS_CUSTOM_DOC_PATH);
+    }
+    allDocDirs.removeDuplicates();
+    return allDocDirs;
 }