The QThread documentation doesn't mention that QTranslator::translate is thread-safe.

However, QTranslator::translate seems to be thread safe by design, as QCoreApplication::translate, that is marked as thread safe, calls this function (guarding it with a read lock only).

Note that a (guaranteed) thread safe QTranslator::translate function may be beneficial in a multi client environment, f.ex. a webserver configuration. This allow the application to share the translator object between multiple sessions.