diff --git a/src/plugins/python/pythonutils.cpp b/src/plugins/python/pythonutils.cpp
index af1c42b5ab9..f679fe2b0fa 100644
--- a/src/plugins/python/pythonutils.cpp
+++ b/src/plugins/python/pythonutils.cpp
@@ -98,6 +98,8 @@ static QString pythonName(const FilePath &pythonPath)
 
 FilePath getPylsModulePath(CommandLine pylsCommand)
 {
+    static QMutex mutex; // protect the access to the cache
+    QMutexLocker locker(&mutex);
     static QMap<FilePath, FilePath> cache;
     const FilePath &modulePath = cache.value(pylsCommand.executable());
     if (!modulePath.isEmpty())