diff --git a/src/kicontheme.cpp b/src/kicontheme.cpp
--- a/src/kicontheme.cpp
+++ b/src/kicontheme.cpp
@@ -31,6 +31,7 @@
 #include <QSet>
 #include <QFileInfo>
 #include <QDir>
+#include <QDirIterator>
 #include <QDebug>
 #include <QResource>
 
@@ -48,6 +49,8 @@
 // For this reason we use AppDataLocation: BINDIR/data on Windows, Resources on OS X
 void initRCCIconTheme()
 {
+    // old variant: one RCC file that will be enforced as icon theme
+    // to be compatible: if this succeeds, we don't try the new variant of looking up multiple rcc files!
     const QString iconThemeRcc = QStandardPaths::locate(QStandardPaths::AppDataLocation, QStringLiteral("icontheme.rcc"));
     if (!iconThemeRcc.isEmpty()) {
         const QString iconThemeName = QStringLiteral("kf5_rcc_theme");
@@ -59,14 +62,28 @@
                 QIcon::setThemeName(iconThemeName); // Qt looks under :/icons automatically
                 // Tell KIconTheme about the theme, in case KIconLoader is used directly
                 *_themeOverride() = iconThemeName;
+                // stop here, we have found a valid rcc that shall be used!
+                return;
             } else {
                 qWarning() << "No index.theme found in" << iconThemeRcc;
                 QResource::unregisterResource(iconThemeRcc, iconSubdir);
             }
         } else {
             qWarning() << "Invalid rcc file" << iconThemeRcc;
         }
     }
+
+    // new variant: load all rcc files we find, assume the have internally proper :/icons/<theme>/... naming
+    // TODO: we might want to use QLibrary and load the stuff as shared libraries to have mmap on all platforms for the data!
+    for (const auto &iconDir : QStandardPaths::locateAll(QStandardPaths::AppDataLocation, QStringLiteral("icons"), QStandardPaths::LocateDirectory)) {
+        QDirIterator it(iconDir, QStringList() << QLatin1String("*.rcc"), QDir::Files);
+        while (it.hasNext()) {
+            const auto iconFile = it.next();
+            if (!QResource::registerResource(iconFile)) {
+                qWarning() << "Invalid rcc file" << iconFile;
+            }
+        }
+    }
 }
 Q_COREAPP_STARTUP_FUNCTION(initRCCIconTheme)