diff --git a/gui/projectfile.h b/gui/projectfile.h
index 4f775beb4..ba12adad0 100644
--- a/gui/projectfile.h
+++ b/gui/projectfile.h
@@ -40,7 +40,7 @@ class ProjectFile : public QObject {
 
 public:
     explicit ProjectFile(QObject *parent = 0);
-    ProjectFile(const QString &filename, QObject *parent = 0);
+    explicit ProjectFile(const QString &filename, QObject *parent = 0);
 
     /**
      * @brief Read the project file.
diff --git a/gui/projectfiledialog.h b/gui/projectfiledialog.h
index 58eaada72..e9882bfc7 100644
--- a/gui/projectfiledialog.h
+++ b/gui/projectfiledialog.h
@@ -42,7 +42,7 @@ class ProjectFile;
 class ProjectFileDialog : public QDialog {
     Q_OBJECT
 public:
-    ProjectFileDialog(ProjectFile *projectFile, QWidget *parent = 0);
+    explicit ProjectFileDialog(ProjectFile *projectFile, QWidget *parent = 0);
     virtual ~ProjectFileDialog();
 
 private: