diff --git a/plugins/problemreporter/problemhighlighter.cpp b/plugins/problemreporter/problemhighlighter.cpp
--- a/plugins/problemreporter/problemhighlighter.cpp
+++ b/plugins/problemreporter/problemhighlighter.cpp
@@ -100,6 +100,17 @@
         return;
 
     iface->registerTextHintProvider(&m_textHintProvider);
+
+    if (KTextEditor::MarkInterface* markIface = dynamic_cast<KTextEditor::MarkInterface*>(m_document.data())) {
+        // FIXME: hardcoded pixel sizes should not be used here, but the KTextEditor API seems to require it
+        static QPixmap errorPixmap = QIcon::fromTheme(QStringLiteral("dialog-error")).pixmap(QSize(22, 22));
+        static QPixmap warningPixmap = QIcon::fromTheme(QStringLiteral("dialog-warning")).pixmap(QSize(22, 22));
+        // TODO: also add icons for information and TODO markers?
+        // static QPixmap infoPixmap = QIcon::fromTheme(QStringLiteral("dialog-information")).pixmap(QSize(22, 22));
+        markIface->setMarkPixmap(KTextEditor::MarkInterface::Warning, warningPixmap);
+        markIface->setMarkPixmap(KTextEditor::MarkInterface::Error, errorPixmap);
+    }
+
 }
 
 ProblemTextHintProvider::ProblemTextHintProvider(ProblemHighlighter* highlighter)