I wouldn't assume that. QLatin1String latinStr("Adiós"); qDebug() << latinStr << newStr; Gives: "Adi\u00C3\u00B3s" A workaround that you can try: QString unicodeStr = "some Uniocode හාහාහා %1"; QString newStr = unicodeStr.arg(QString::fromUtf8(latinStr.data())); qDebug() << newStr;