diff --git a/src/gui/kernel/qplatformdialoghelper.cpp b/src/gui/kernel/qplatformdialoghelper.cpp
index 0224fb2c61..fbc635cc93 100644
--- a/src/gui/kernel/qplatformdialoghelper.cpp
+++ b/src/gui/kernel/qplatformdialoghelper.cpp
@@ -15,6 +15,7 @@
 #include <QtCore/QUrl>
 #include <QtCore/QVariant>
 #include <QtGui/QColor>
+#include <QtGui/QPixmap>
 
 #include <algorithm>
 
@@ -774,6 +775,7 @@ public:
     QPlatformDialogHelper::StandardButtons buttons;
     QList<QMessageDialogOptions::CustomButton> customButtons;
     int nextCustomButtonId;
+    QPixmap iconPixmap;
 };
 
 QMessageDialogOptions::QMessageDialogOptions(QMessageDialogOptionsPrivate *dd)
@@ -825,6 +827,16 @@ void QMessageDialogOptions::setIcon(Icon icon)
     d->icon = icon;
 }
 
+void QMessageDialogOptions::setIconPixmap(const QPixmap &pixmap)
+{
+    d->iconPixmap = pixmap;
+}
+
+QPixmap QMessageDialogOptions::iconPixmap() const
+{
+    return d->iconPixmap;
+}
+
 QString QMessageDialogOptions::text() const
 {
     return d->text;
diff --git a/src/gui/kernel/qplatformdialoghelper.h b/src/gui/kernel/qplatformdialoghelper.h
index 83857ba82e..2d3138270f 100644
--- a/src/gui/kernel/qplatformdialoghelper.h
+++ b/src/gui/kernel/qplatformdialoghelper.h
@@ -416,6 +416,9 @@ public:
     void setIcon(Icon icon);
     Icon icon() const;
 
+    void setIconPixmap(const QPixmap &pixmap);
+    QPixmap iconPixmap() const;
+
     void setText(const QString &text);
     QString text() const;
 
diff --git a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
index c21fbc2ce4..3d3970953d 100644
--- a/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
+++ b/src/plugins/platforms/cocoa/qcocoamessagedialog.mm
@@ -12,6 +12,7 @@
 
 #include <QtGui/qtextdocument.h>
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qcoregraphics_p.h>
 #include <QtGui/qpa/qplatformtheme.h>
 
 #include <AppKit/NSAlert.h>
@@ -90,8 +91,18 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
     m_alert.messageText = text.toNSString();
     m_alert.informativeText = toPlainText(options()->informativeText()).toNSString();
 
-    switch (options()->icon()) {
-    case QMessageDialogOptions::NoIcon:
+    switch (auto standardIcon = options()->icon()) {
+    case QMessageDialogOptions::NoIcon: {
+        // We only reflect the pixmap icon if the standard icon is unset,
+        // as setting a standard icon will also set a corresponding pixmap
+        // icon, which we don't want since it conflicts with the platform.
+        // If the user has set an explicit pixmap icon however, the standard
+        // icon will be NoIcon, so we're good.
+        QPixmap iconPixmap = options()->iconPixmap();
+        if (!iconPixmap.isNull())
+            m_alert.icon = [NSImage imageFromQImage:iconPixmap.toImage()];
+        break;
+    }
     case QMessageDialogOptions::Information:
     case QMessageDialogOptions::Question:
         [m_alert setAlertStyle:NSAlertStyleInformational];
@@ -104,8 +115,6 @@ bool QCocoaMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality w
         break;
     }
 
-    // FIXME: Propagate iconPixmap through dialog options
-
     bool defaultButtonAdded = false;
     bool cancelButtonAdded = false;
 
diff --git a/src/widgets/dialogs/qmessagebox.cpp b/src/widgets/dialogs/qmessagebox.cpp
index 95aaf45e7c..52a6d9282e 100644
--- a/src/widgets/dialogs/qmessagebox.cpp
+++ b/src/widgets/dialogs/qmessagebox.cpp
@@ -2719,6 +2719,7 @@ void QMessageBoxPrivate::helperPrepareShow(QPlatformDialogHelper *)
     options->setDetailedText(q->detailedText());
 #endif
     options->setIcon(helperIcon(q->icon()));
+    options->setIconPixmap(q->iconPixmap());
     options->setStandardButtons(helperStandardButtons(q));
 }