Robert Simms (20 March 1761 – 1843) was an Irish radical, and a founding member in Belfast of the Society of United Irishmen.
Opposed to insurrection in the absence of French assistance, he resigned his military commission in the Society on the eve of the 1798 rebellion.
Following the French declaration of war on Britain in February 1793, the movement was outlawed and went underground from 1794 as they became more determined to force a revolt against British rule.
However, the suppression of a bloody preemptive rebellion, which broke out in Leitrim in 1793, led to the former faction prevailing and links were forged with the revolutionary French government with instructions to wait sent to all of the United Irish membership.
The appointment was met reluctantly, however, as Simms felt his lack of military experience counted against him being an effective leader.