diff --git a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
index 9771c1115b9..69b487534a0 100644
--- a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
+++ b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
@@ -439,6 +439,7 @@ public:
         , m_projectPart(projectPart)
     {
         addLanguageOptions();
+        addGlobalDiagnosticOptions(); // Before addDiagnosticOptions() so users still can overwrite.
         addDiagnosticOptions();
         addGlobalOptions();
         addPrecompiledHeaderOptions();
@@ -519,6 +520,15 @@ private:
         addXclangArg("-plugin-arg-clang-lazy", checks);
     }
 
+    void addGlobalDiagnosticOptions()
+    {
+        m_options.append({
+            // Avoid undesired warnings from e.g. Q_OBJECT
+            QStringLiteral("-Wno-unknown-pragmas"),
+            QStringLiteral("-Wno-unknown-warning-option")
+        });
+    }
+
     void addGlobalOptions()
     {
         if (!m_projectPart.project)
diff --git a/src/plugins/cpptools/clangdiagnosticconfigsmodel.cpp b/src/plugins/cpptools/clangdiagnosticconfigsmodel.cpp
index 4580e82801d..d06afa909b0 100644
--- a/src/plugins/cpptools/clangdiagnosticconfigsmodel.cpp
+++ b/src/plugins/cpptools/clangdiagnosticconfigsmodel.cpp
@@ -33,11 +33,6 @@
 
 namespace CppTools {
 
-static QStringList commonWarnings()
-{
-    return { QStringLiteral("-Wno-unknown-pragmas") };
-}
-
 static void addConfigForQuestionableConstructs(ClangDiagnosticConfigsModel &model)
 {
     ClangDiagnosticConfig config;
@@ -48,7 +43,7 @@ static void addConfigForQuestionableConstructs(ClangDiagnosticConfigsModel &mode
     config.setClangOptions(QStringList{
         QStringLiteral("-Wall"),
         QStringLiteral("-Wextra"),
-    } + commonWarnings());
+    });
 
     model.appendOrUpdate(config);
 }
@@ -60,7 +55,7 @@ static void addConfigForPedanticWarnings(ClangDiagnosticConfigsModel &model)
     config.setDisplayName(QCoreApplication::translate("ClangDiagnosticConfigsModel",
                                                       "Pedantic Warnings"));
     config.setIsReadOnly(true);
-    config.setClangOptions(QStringList{QStringLiteral("-Wpedantic")} + commonWarnings());
+    config.setClangOptions(QStringList{QStringLiteral("-Wpedantic")});
 
     model.appendOrUpdate(config);
 }
@@ -86,7 +81,7 @@ static void addConfigForAlmostEveryWarning(ClangDiagnosticConfigsModel &model)
         QStringLiteral("-Wno-switch-enum"),
         QStringLiteral("-Wno-missing-prototypes"), // Not optimal for C projects.
         QStringLiteral("-Wno-used-but-marked-unused"), // e.g. QTest::qWait
-    } + commonWarnings());
+    });
 
     model.appendOrUpdate(config);
 }