diff --git a/src/plugins/valgrind/callgrind/callgrindparser.h b/src/plugins/valgrind/callgrind/callgrindparser.h
index 7d53b8abc38..40062f515d7 100644
--- a/src/plugins/valgrind/callgrind/callgrindparser.h
+++ b/src/plugins/valgrind/callgrind/callgrindparser.h
@@ -50,7 +50,7 @@ class Parser : public QObject
     Q_OBJECT
 
 public:
-    explicit Parser(QObject *parent = 0);
+    explicit Parser(QObject *parent = nullptr);
     ~Parser() override;
 
     // get and take ownership of the parsing results. If this function is not called the repository
diff --git a/src/plugins/valgrind/callgrind/callgrindproxymodel.h b/src/plugins/valgrind/callgrind/callgrindproxymodel.h
index 994e8ed67f4..822fee2109d 100644
--- a/src/plugins/valgrind/callgrind/callgrindproxymodel.h
+++ b/src/plugins/valgrind/callgrind/callgrindproxymodel.h
@@ -38,7 +38,7 @@ class DataProxyModel : public QSortFilterProxyModel
     Q_OBJECT
 
 public:
-    explicit DataProxyModel(QObject *parent = 0);
+    explicit DataProxyModel(QObject *parent = nullptr);
 
     void setSourceModel(QAbstractItemModel *sourceModel) override;
 
diff --git a/src/plugins/valgrind/callgrind/callgrindstackbrowser.h b/src/plugins/valgrind/callgrind/callgrindstackbrowser.h
index b886b90d145..7655da03975 100644
--- a/src/plugins/valgrind/callgrind/callgrindstackbrowser.h
+++ b/src/plugins/valgrind/callgrind/callgrindstackbrowser.h
@@ -38,7 +38,7 @@ class StackBrowser : public QObject
     Q_OBJECT
 
 public:
-    explicit StackBrowser(QObject *parent = 0);
+    explicit StackBrowser(QObject *parent = nullptr);
 
     void select(const Function *item);
     const Function *current() const;
diff --git a/src/plugins/valgrind/valgrindrunner.h b/src/plugins/valgrind/valgrindrunner.h
index b45e3e3d7e2..b2dcf754fdb 100644
--- a/src/plugins/valgrind/valgrindrunner.h
+++ b/src/plugins/valgrind/valgrindrunner.h
@@ -41,7 +41,7 @@ class ValgrindRunner : public QObject
     Q_OBJECT
 
 public:
-    explicit ValgrindRunner(QObject *parent = 0);
+    explicit ValgrindRunner(QObject *parent = nullptr);
     ~ValgrindRunner() override;
 
     void setValgrindExecutable(const QString &executable);