diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -53,6 +53,12 @@
 option(QRC_SYNTAX "Bundle the syntax definition files inside the library as resources" ON)
 add_feature_info(SYNTAX_RESOURCE ${QRC_SYNTAX} "Bundle the syntax definition files inside the library as resources")
 
+#
+# allow to turn of lookup for syntax files and themes via QStandardPaths
+#
+option(NO_STANDARD_PATHS "Skip lookup of syntax and theme definitions in QStandardPaths locations" OFF)
+add_feature_info(FEATURE_NO_STANDARD_PATHS ${NO_STANDARD_PATHS} "Skip lookup of syntax and theme definitions in QStandardPaths locations")
+
 #
 # API documentation
 #
@@ -71,6 +77,11 @@
     add_definitions(-DHAS_SYNTAX_RESOURCE)
 endif()
 
+# skip standard paths?
+if (NO_STANDARD_PATHS)
+    add_definitions(-DNO_STANDARD_PATHS)
+endif()
+
 #
 # Actually build the stuff
 #
diff --git a/autotests/test-config.h.in b/autotests/test-config.h.in
--- a/autotests/test-config.h.in
+++ b/autotests/test-config.h.in
@@ -41,6 +41,5 @@
 #else
     repository.addCustomSearchPath(QStringLiteral("@CMAKE_SOURCE_DIR@/data"));
     repository.addCustomSearchPath(QStringLiteral("@CMAKE_BINARY_DIR@/data"));
-    repository.reload();
 #endif
 }
diff --git a/src/lib/repository.h b/src/lib/repository.h
--- a/src/lib/repository.h
+++ b/src/lib/repository.h
@@ -82,39 +82,48 @@
  * additional files from disk is supported as well.
  *
  * Loading syntax Definition files works as follows:
+ *
  * -# First, all syntax highlighting files are loaded that are located in
  *    QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/syntax"), QStandardPaths::LocateDirectory);
  *    Under Unix, this uses $XDG_DATA_HOME and $XDG_DATA_DIRS, which could
  *    map to $HOME/.local5/share/org.kde.syntax-highlighting/syntax and
  *    /usr/share/org.kde.syntax-highlighting/syntax.
+ *
  * -# Next, for backwards compatibility with Kate, all syntax highlighting
  *    files are loaded that are located in
  *    QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("katepart5/syntax"), QStandardPaths::LocateDirectory);
  *    Again, under Unix, this uses $XDG_DATA_HOME and $XDG_DATA_DIRS, which
  *    could map to $HOME/.local5/share/katepart5/syntax and
  *    /usr/share/katepart5/syntax.
+ *
  * -# Then, all files compiled into the library through resources are loaded.
  *    The internal resource path is ":/org.kde.syntax-highlighting/syntax".
  *    This path should never be touched by other applications.
+ *
  * -# Finally, the search path can be extended by calling addCustomSearchPath().
  *    A custom search path can either be a path on disk or again a path to
- *    a Qt resoruce.
+ *    a Qt resource.
  *
  * Similarly, loading Theme files works as follows:
+ *
  * -# First, all Theme files are loaded that are located in
  *    QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/themes"), QStandardPaths::LocateDirectory);
  *    Under Unix, this uses $XDG_DATA_HOME and $XDG_DATA_DIRS, which could
  *    map to $HOME/.local5/share/org.kde.syntax-highlighting/themes and
  *    /usr/share/org.kde.syntax-highlighting/themes.
+ *
  * -# Then, all files compiled into the library through resources are loaded.
  *    The internal resource path is ":/org.kde.syntax-highlighting/themes".
  *    This path should never be touched by other applications.
+ *
  * -# Finally, all Theme%s located in the paths added addCustomSearchPath()
  *    are loaded.
  *
  * @note Whenever a Definition or a Theme exists twice, the variant with
  *       higher version is used.
  *
+ * @note The QStandardPaths lookup can be disabled by compiling the framework with the -DNO_STANDARD_PATHS define.
+ *
  * @see Definition, Theme, AbstractHighlighter
  * @since 5.28
  */
@@ -210,6 +219,8 @@
      *       Theme%s. Do not append @e syntax or @e themes to @p path
      *       yourself.
      *
+     * @note Calling this triggers a reload() of the repository.
+     *
      * @since 5.39
      */
     void addCustomSearchPath(const QString &path);
diff --git a/src/lib/repository.cpp b/src/lib/repository.cpp
--- a/src/lib/repository.cpp
+++ b/src/lib/repository.cpp
@@ -36,7 +36,10 @@
 #include <QFileInfo>
 #include <QJsonDocument>
 #include <QJsonObject>
+
+#ifndef NO_STANDARD_PATHS
 #include <QStandardPaths>
+#endif
 
 #include <limits>
 
@@ -134,16 +137,20 @@
     // always add invalid default "None" highlighting
     addDefinition(Definition());
 
-    auto dirs = QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/syntax"), QStandardPaths::LocateDirectory);
-    foreach (const auto &dir, dirs)
+    // do lookup in standard paths, if not disabled
+#ifndef NO_STANDARD_PATHS
+    foreach (const auto &dir, QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/syntax"), QStandardPaths::LocateDirectory))
         loadSyntaxFolder(repo, dir);
+
     // backward compatibility with Kate
-    dirs = QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("katepart5/syntax"), QStandardPaths::LocateDirectory);
-    foreach (const auto &dir, dirs)
+    foreach (const auto &dir, QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("katepart5/syntax"), QStandardPaths::LocateDirectory))
         loadSyntaxFolder(repo, dir);
+#endif
 
+    // default resources are always used
     loadSyntaxFolder(repo, QStringLiteral(":/org.kde.syntax-highlighting/syntax"));
 
+    // user given extra paths
     foreach (const auto &path, m_customSearchPaths)
         loadSyntaxFolder(repo, path + QStringLiteral("/syntax"));
 
@@ -158,11 +165,17 @@
     });
 
     // load themes
-    dirs = QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/themes"), QStandardPaths::LocateDirectory);
-    foreach (const auto &dir, dirs)
+
+    // do lookup in standard paths, if not disabled
+#ifndef NO_STANDARD_PATHS
+    foreach (const auto &dir, QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, QStringLiteral("org.kde.syntax-highlighting/themes"), QStandardPaths::LocateDirectory))
         loadThemeFolder(dir);
+#endif
+
+    // default resources are always used
     loadThemeFolder(QStringLiteral(":/org.kde.syntax-highlighting/themes"));
 
+    // user given extra paths
     foreach (const auto &path, m_customSearchPaths)
         loadThemeFolder(path + QStringLiteral("/themes"));
 }