diff --git a/abstract_client.h b/abstract_client.h
--- a/abstract_client.h
+++ b/abstract_client.h
@@ -653,6 +653,8 @@
 
     /**
      * Constrains the desired client size @p size according to a set the window's size hints.
+     *
+     * Default implementation applies only minimum and maximum size constraints.
      */
     virtual QSize constrainClientSize(const QSize &size, SizeMode mode = SizeModeAny) const;
     /**
diff --git a/abstract_client.cpp b/abstract_client.cpp
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -3140,6 +3140,9 @@
         height = 1;
     }
 
+    width = qBound(minSize().width(), width, maxSize().width());
+    height = qBound(minSize().height(), height, maxSize().height());
+
     return QSize(width, height);
 }
 
diff --git a/xdgshellclient.h b/xdgshellclient.h
--- a/xdgshellclient.h
+++ b/xdgshellclient.h
@@ -62,6 +62,8 @@
     QStringList activities() const override;
     QPoint clientContentPos() const override;
     QSize clientSize() const override;
+    QSize minSize() const override;
+    QSize maxSize() const override;
     QRect transparentRect() const override;
     NET::WindowType windowType(bool direct = false, int supported_types = 0) const override;
     void debug(QDebug &stream) const override;
diff --git a/xdgshellclient.cpp b/xdgshellclient.cpp
--- a/xdgshellclient.cpp
+++ b/xdgshellclient.cpp
@@ -336,6 +336,24 @@
     return m_windowGeometry.size().boundedTo(boundingRect.size());
 }
 
+QSize XdgShellClient::minSize() const
+{
+    // Window rules are applied only to xdg-toplevel clients.
+    if (m_xdgShellSurface) {
+        return rules()->checkMinSize(m_xdgShellSurface->minimumSize());
+    }
+    return QSize(0, 0);
+}
+
+QSize XdgShellClient::maxSize() const
+{
+    // Window rules are applied only to xdg-toplevel clients.
+    if (m_xdgShellSurface) {
+        return rules()->checkMaxSize(m_xdgShellSurface->maximumSize());
+    }
+    return QSize(INT_MAX, INT_MAX);
+}
+
 void XdgShellClient::debug(QDebug &stream) const
 {
     stream.nospace();