Ugolino Lorenzetti (or Ugolino-Lorenzetti) is an invented name for an unknown Italian artist midway between the styles of Ugolino da Siena and the Lorenzetti.
Also known as the Ovile Master (Maestro di San Pietro Ovile), he has been tentatively identified with Bartolommeo Bulgarini (active c. 1347-d. 1378) who is known to have been a painter.
