diff --git a/src/kiconengine.cpp b/src/kiconengine.cpp
--- a/src/kiconengine.cpp
+++ b/src/kiconengine.cpp
@@ -21,6 +21,7 @@
 #include <kiconloader.h>
 
 #include <KIconTheme>
+#include <QCoreApplication>
 #include <QPainter>
 #include <QSet>
 
@@ -94,10 +95,8 @@
         return pm;
     }
 
-    const QSize scaledSize = size / scale;
-
     const int kstate = qIconModeToKIconState(mode);
-    const int iconSize = qMin(scaledSize.width(), scaledSize.height());
+    const int iconSize = qMin(size.width(), size.height());
     QPixmap pix = mIconLoader.data()->loadScaledIcon(mIconName, KIconLoader::Desktop, scale, iconSize, kstate, mOverlays);
 
     if (pix.size() == size) {
diff --git a/src/kiconloader.cpp b/src/kiconloader.cpp
--- a/src/kiconloader.cpp
+++ b/src/kiconloader.cpp
@@ -28,6 +28,7 @@
 #include <assert.h>
 
 #include <QCache>
+#include <QCoreApplication>
 #include <QFileInfo>
 #include <QDir>
 #include <QBuffer>
@@ -954,7 +955,11 @@
     }
 
     if (size != 0) {
-        reader.setScaledSize(QSize(size * scale, size * scale));
+        if (QCoreApplication::instance()->testAttribute(Qt::AA_UseHighDpiPixmaps)) {
+            reader.setScaledSize(QSize(size, size));
+        } else {
+            reader.setScaledSize(QSize(size * scale, size * scale));
+        }
     }
 
     return reader.read();
diff --git a/src/kicontheme.cpp b/src/kicontheme.cpp
--- a/src/kicontheme.cpp
+++ b/src/kicontheme.cpp
@@ -191,27 +191,28 @@
     // - Prefer directories that allow a downscaling even if the difference to
     //   the requested size is bigger than a directory where an upscaling is required.
     for (KIconThemeDir *dir : dirs) {
+        const int scaledDirSize = dir->size() * dir->scale();
         if (dir->scale() != integerScale) {
             continue;
         }
 
         if (match == KIconLoader::MatchExact) {
-            if ((dir->type() == KIconLoader::Fixed) && (dir->size() != size)) {
+            if ((dir->type() == KIconLoader::Fixed) && (scaledDirSize != size)) {
                 continue;
             }
             if ((dir->type() == KIconLoader::Scalable) &&
-                    ((size < dir->minSize()) || (size > dir->maxSize()))) {
+                    ((size < dir->minSize() * scale) || (size > dir->maxSize() * scale))) {
                 continue;
             }
             if ((dir->type() == KIconLoader::Threshold) &&
-                    (abs(dir->size() - size) > dir->threshold())) {
+                    (abs(scaledDirSize - size) > dir->threshold())) {
                 continue;
             }
         } else {
             // dw < 0 means need to scale up to get an icon of the requested size.
             // Upscaling should only be done if no larger icon is available.
             if (dir->type() == KIconLoader::Fixed) {
-                dw = dir->size() - size;
+                dw = scaledDirSize - size;
             } else if (dir->type() == KIconLoader::Scalable) {
                 if (size < dir->minSize()) {
                     dw = dir->minSize() - size;
@@ -221,10 +222,10 @@
                     dw = 0;
                 }
             } else if (dir->type() == KIconLoader::Threshold) {
-                if (size < dir->size() - dir->threshold()) {
-                    dw = dir->size() - dir->threshold() - size;
-                } else if (size > dir->size() + dir->threshold()) {
-                    dw = dir->size() + dir->threshold() - size;
+                if (size < scaledDirSize - dir->threshold()) {
+                    dw = scaledDirSize - dir->threshold() - size;
+                } else if (size > scaledDirSize + dir->threshold()) {
+                    dw = scaledDirSize + dir->threshold() - size;
                 } else {
                     dw = 0;
                 }