diff --git a/kdecoration/breezedecoration.h b/kdecoration/breezedecoration.h
--- a/kdecoration/breezedecoration.h
+++ b/kdecoration/breezedecoration.h
@@ -150,6 +150,11 @@
         //* active state change opacity
         qreal m_opacity = 0;
 
+        qreal m_scalingFactor;
+
+        qreal frameRadius(qreal bias = 0) {
+            return (Metrics::Frame_FrameRadius + bias) * m_scalingFactor;
+        }
     };
 
     bool Decoration::hasBorders() const
diff --git a/kdecoration/breezedecoration.cpp b/kdecoration/breezedecoration.cpp
--- a/kdecoration/breezedecoration.cpp
+++ b/kdecoration/breezedecoration.cpp
@@ -371,6 +371,10 @@
     void Decoration::reconfigure()
     {
 
+        // this only affects X11
+        // on Wayland it's always 1
+        m_scalingFactor = qMax(1.0, QGuiApplication::primaryScreen()->logicalDotsPerInch() / 96.0);
+
         m_internalSettings = SettingsProvider::self()->internalSettings( this );
 
         // animation
@@ -534,7 +538,7 @@
             // clip away the top part
             if( !hideTitleBar() ) painter->setClipRect(0, borderTop(), size().width(), size().height() - borderTop(), Qt::IntersectClip);
 
-            if( s->isAlphaChannelSupported() ) painter->drawRoundedRect(rect(), Metrics::Frame_FrameRadius, Metrics::Frame_FrameRadius);
+            if( s->isAlphaChannelSupported() ) painter->drawRoundedRect(rect(), frameRadius(), frameRadius());
             else painter->drawRect( rect() );
 
             painter->restore();
@@ -592,19 +596,19 @@
 
         } else if( c->isShaded() ) {
 
-            painter->drawRoundedRect(titleRect, Metrics::Frame_FrameRadius, Metrics::Frame_FrameRadius);
+            painter->drawRoundedRect(titleRect, frameRadius(), frameRadius());
 
         } else {
 
             painter->setClipRect(titleRect, Qt::IntersectClip);
 
             // the rect is made a little bit larger to be able to clip away the rounded corners at the bottom and sides
             painter->drawRoundedRect(titleRect.adjusted(
-                isLeftEdge() ? -Metrics::Frame_FrameRadius:0,
-                isTopEdge() ? -Metrics::Frame_FrameRadius:0,
-                isRightEdge() ? Metrics::Frame_FrameRadius:0,
-                Metrics::Frame_FrameRadius),
-                Metrics::Frame_FrameRadius, Metrics::Frame_FrameRadius);
+                isLeftEdge() ? -frameRadius():0,
+                isTopEdge() ? -frameRadius():0,
+                isRightEdge() ? frameRadius():0,
+                frameRadius()),
+                frameRadius(), frameRadius());
 
         }
 
@@ -774,17 +778,16 @@
             painter.setCompositionMode(QPainter::CompositionMode_DestinationOut);
             painter.drawRoundedRect(
                 innerRect,
-                Metrics::Frame_FrameRadius + 0.5,
-                Metrics::Frame_FrameRadius + 0.5);
-
+                frameRadius(0.5),
+                frameRadius(0.5));
             // Draw outline.
-            painter.setPen(withOpacity(g_shadowColor, 0.2 * strength));
+            painter.setPen(QPen(withOpacity(g_shadowColor, 0.2 * strength), m_scalingFactor * m_scalingFactor));
             painter.setBrush(Qt::NoBrush);
             painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
             painter.drawRoundedRect(
                 innerRect,
-                Metrics::Frame_FrameRadius - 0.5,
-                Metrics::Frame_FrameRadius - 0.5);
+                frameRadius(-0.5),
+                frameRadius(-0.5));
 
             painter.end();