Thomas Lyell [or Lyel] was a Scottish clergyman associated with the diocese of Ross in the late 14th century and early 15th century. After William de Tarbat, Subdean of Ross, was elected Dean of Ross, on 1 May 1395, Thomas was provided as William's successor. Thomas however does not seem to have secured the position, losing out to John de Kylwos, a relative of the Bishop of Ross, Alexander de Kylwos.