diff --git a/abstract_client.cpp b/abstract_client.cpp
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -3106,6 +3106,8 @@
 
 /**
  * Constrains the client size @p size according to a set of the window's size hints.
+ *
+ * Default implementation applies only minimum and maximum size constraints.
  */
 QSize AbstractClient::constrainClientSize(const QSize &size, SizeMode mode) const
 {
@@ -3123,6 +3125,12 @@
         height = 1;
     }
 
+    const QSize minimumSize = minSize();
+    const QSize maximumSize = maxSize();
+
+    width = qBound(minimumSize.width(), width, maximumSize.width());
+    height = qBound(minimumSize.height(), height, maximumSize.height());
+
     return QSize(width, height);
 }
 
diff --git a/xdgshellclient.h b/xdgshellclient.h
--- a/xdgshellclient.h
+++ b/xdgshellclient.h
@@ -63,6 +63,8 @@
     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
@@ -345,6 +345,22 @@
     return m_windowGeometry.size().boundedTo(boundingRect.size());
 }
 
+QSize XdgShellClient::minSize() const
+{
+    if (m_xdgShellToplevel) {
+        return rules()->checkMinSize(m_xdgShellToplevel->minimumSize());
+    }
+    return QSize(0, 0);
+}
+
+QSize XdgShellClient::maxSize() const
+{
+    if (m_xdgShellToplevel) {
+        return rules()->checkMaxSize(m_xdgShellToplevel->maximumSize());
+    }
+    return QSize(INT_MAX, INT_MAX);
+}
+
 void XdgShellClient::debug(QDebug &stream) const
 {
     stream.nospace();