diff --git a/src/plugins/autotest/itestparser.cpp b/src/plugins/autotest/itestparser.cpp
index 99b760f78bd..9438fe4caf1 100644
--- a/src/plugins/autotest/itestparser.cpp
+++ b/src/plugins/autotest/itestparser.cpp
@@ -5,6 +5,7 @@
 
 #include <coreplugin/editormanager/editormanager.h>
 #include <cppeditor/cppmodelmanager.h>
+#include <projectexplorer/projectmanager.h>
 #include <utils/textfileformat.h>
 #include <utils/algorithm.h>
 
@@ -105,6 +106,31 @@ bool CppParser::precompiledHeaderContains(const CPlusPlus::Snapshot &snapshot,
                                                });
 }
 
+std::optional<QSet<FilePath>> CppParser::filesContainingMacro(const QByteArray &macroName)
+{
+    // safety net to avoid adding some option
+    static const bool noPrefilter = qtcEnvironmentVariableIsSet("QTC_AUTOTEST_DISABLE_PREFILTER");
+    if (noPrefilter)
+        return std::nullopt;
+
+    QSet<FilePath> result;
+    CppEditor::ProjectInfo::ConstPtr infos = CppEditor::CppModelManager::projectInfo(
+                ProjectExplorer::ProjectManager::startupProject());
+    if (!infos)
+        return std::nullopt;
+
+    const auto projectParts = infos->projectParts();
+    for (const auto &pp : projectParts) {
+        if (!pp->selectedForBuilding)
+            continue;
+
+        const ProjectExplorer::Macros macros = pp->projectMacros;
+        if (Utils::anyOf(pp->projectMacros, Utils::equal(&ProjectExplorer::Macro::key, macroName)))
+            result.unite(Utils::transform<QSet>(pp->files, &CppEditor::ProjectFile::path));
+    }
+    return std::make_optional(result);
+}
+
 void CppParser::release()
 {
     m_cppSnapshot = CPlusPlus::Snapshot();
diff --git a/src/plugins/autotest/itestparser.h b/src/plugins/autotest/itestparser.h
index 93233bd7a97..6e3305dd6ea 100644
--- a/src/plugins/autotest/itestparser.h
+++ b/src/plugins/autotest/itestparser.h
@@ -9,6 +9,8 @@
 #include <cppeditor/cppworkingcopy.h>
 #include <qmljs/qmljsdocument.h>
 
+#include <optional>
+
 QT_BEGIN_NAMESPACE
 template <class T>
 class QPromise;
@@ -76,6 +78,9 @@ public:
     static bool precompiledHeaderContains(const CPlusPlus::Snapshot &snapshot,
                                           const Utils::FilePath &filePath,
                                           const QRegularExpression &headerFileRegex);
+    // returns all files of the startup project whose ProjectPart has the given \a macroName
+    // set as a project define
+    static std::optional<QSet<Utils::FilePath>> filesContainingMacro(const QByteArray &macroName);
 
 protected:
     CPlusPlus::Snapshot m_cppSnapshot;
diff --git a/src/plugins/autotest/qtest/qttestparser.cpp b/src/plugins/autotest/qtest/qttestparser.cpp
index 824f4860a45..a74944b7b64 100644
--- a/src/plugins/autotest/qtest/qttestparser.cpp
+++ b/src/plugins/autotest/qtest/qttestparser.cpp
@@ -295,6 +295,9 @@ static bool isQObject(const CPlusPlus::Document::Ptr &declaringDoc)
 bool QtTestParser::processDocument(QPromise<TestParseResultPtr> &promise,
                                    const FilePath &fileName)
 {
+    if (!m_prefilteredFiles.contains(fileName))
+        return false;
+
     CPlusPlus::Document::Ptr doc = document(fileName);
     if (doc.isNull())
         return false;
@@ -418,6 +421,12 @@ void QtTestParser::init(const QSet<FilePath> &filesToParse, bool fullParse)
         m_testCases = QTestUtils::testCaseNamesForFiles(framework(), filesToParse);
         m_alternativeFiles = QTestUtils::alternativeFiles(framework(), filesToParse);
     }
+
+    if (std::optional<QSet<Utils::FilePath>> prefiltered = filesContainingMacro("QT_TESTLIB_LIB"))
+        m_prefilteredFiles = prefiltered->intersect(filesToParse);
+    else
+        m_prefilteredFiles = filesToParse;
+
     CppParser::init(filesToParse, fullParse);
 }
 
@@ -425,6 +434,7 @@ void QtTestParser::release()
 {
     m_testCases.clear();
     m_alternativeFiles.clear();
+    m_prefilteredFiles.clear();
     CppParser::release();
 }
 
diff --git a/src/plugins/autotest/qtest/qttestparser.h b/src/plugins/autotest/qtest/qttestparser.h
index ece2bc639c5..9f8c44593f0 100644
--- a/src/plugins/autotest/qtest/qttestparser.h
+++ b/src/plugins/autotest/qtest/qttestparser.h
@@ -57,6 +57,7 @@ private:
                                          const QString &projectFile) const;
     QHash<Utils::FilePath, TestCases> m_testCases;
     QMultiHash<Utils::FilePath, Utils::FilePath> m_alternativeFiles;
+    QSet<Utils::FilePath> m_prefilteredFiles;
 };
 
 } // namespace Internal
diff --git a/src/plugins/autotest/quick/quicktestparser.cpp b/src/plugins/autotest/quick/quicktestparser.cpp
index eaba2299588..ef0bba8cc89 100644
--- a/src/plugins/autotest/quick/quicktestparser.cpp
+++ b/src/plugins/autotest/quick/quicktestparser.cpp
@@ -28,8 +28,7 @@
 using namespace QmlJS;
 using namespace Utils;
 
-namespace Autotest {
-namespace Internal {
+namespace Autotest::Internal {
 
 TestTreeItem *QuickTestParseResult::createTestTreeItem() const
 {
@@ -359,6 +358,11 @@ void QuickTestParser::init(const QSet<FilePath> &filesToParse, bool fullParse)
 
     m_checkForDerivedTests = theQtTestFramework().quickCheckForDerivedTests();
 
+    if (std::optional<QSet<Utils::FilePath>> prefiltered = filesContainingMacro("QT_QMLTEST_LIB"))
+        m_prefilteredFiles = prefiltered->intersect(filesToParse);
+    else
+        m_prefilteredFiles = filesToParse;
+
     CppParser::init(filesToParse, fullParse);
 }
 
@@ -366,6 +370,7 @@ void QuickTestParser::release()
 {
     m_qmlSnapshot = Snapshot();
     m_proFilesForQmlFiles.clear();
+    m_prefilteredFiles.clear();
     CppParser::release();
 }
 
@@ -384,6 +389,9 @@ bool QuickTestParser::processDocument(QPromise<TestParseResultPtr> &promise,
                                                 m_checkForDerivedTests);
     }
 
+    if (!m_prefilteredFiles.contains(fileName))
+        return false;
+
    CPlusPlus::Document::Ptr cppdoc = document(fileName);
    if (cppdoc.isNull() || !includesQtQuickTest(cppdoc, m_cppSnapshot))
        return false;
@@ -396,5 +404,4 @@ FilePath QuickTestParser::projectFileForMainCppFile(const FilePath &fileName) co
     return m_mainCppFiles.contains(fileName) ? m_mainCppFiles.value(fileName) : FilePath();
 }
 
-} // namespace Internal
-} // namespace Autotest
+} // namespace Autotest::Internal
diff --git a/src/plugins/autotest/quick/quicktestparser.h b/src/plugins/autotest/quick/quicktestparser.h
index dfd71333ead..e93fa9605f4 100644
--- a/src/plugins/autotest/quick/quicktestparser.h
+++ b/src/plugins/autotest/quick/quicktestparser.h
@@ -44,6 +44,7 @@ private:
     QFileSystemWatcher m_directoryWatcher;
     QMap<QString, QMap<QString, QDateTime> > m_watchedFiles;
     QMap<Utils::FilePath, Utils::FilePath> m_mainCppFiles;
+    QSet<Utils::FilePath> m_prefilteredFiles;
     bool m_checkForDerivedTests = false;
 };