Tahmasp or Tahmasb may refer to:
Tahmasp I (reigned 1524–1576), Safavid shah of Persia Tahmasp II (reigned 1729–1732), Safavid shah of Persia Tahmasp Khan Jalayer, a general of Nader Shah Tahmasp Mirza Moayyed od-Dowleh (1805–1879/80), Qajar prince Tahmasb Mazaheri, Iranian politician and economist Tahmasb Quli, various people so named, including Nader Shah Tahmasb, a character in the Shahnameh, an epic poem written between 977 and 1010