diff --git a/interfaces/viewerinterface.h b/interfaces/viewerinterface.h
index c3de2e9bb..1418c602d 100644
--- a/interfaces/viewerinterface.h
+++ b/interfaces/viewerinterface.h
@@ -23,7 +23,7 @@ namespace Okular {
  * This interface can be used to control some more or less advanced features of a document
  * viewer.
  */
-class ViewerInterface
+class OKULAR_EXPORT ViewerInterface
 {
     public:
         virtual ~ViewerInterface() {}
diff --git a/kdocumentviewer.h b/kdocumentviewer.h
index 2f77610d7..f99c69ef4 100644
--- a/kdocumentviewer.h
+++ b/kdocumentviewer.h
@@ -10,6 +10,8 @@
 #ifndef _KDOCUMENTVIEWER_H_
 #define _KDOCUMENTVIEWER_H_
 
+#include "okular_part_export.h"
+
 #include <QtCore/QStringList>
 
 class KUrl;
@@ -19,7 +21,7 @@ class KUrl;
  *
  * This interface describe briefly the basic functions of a document viewer.
  */
-class KDocumentViewer
+class OKULAR_PART_EXPORT KDocumentViewer
 {
     public:
         virtual ~KDocumentViewer() {}