In 1793 the French king was beheaded and France declared war on Britain. The conflict lasted 20 years and involved most of Europe. The 10th and 11th fought in Holland, Egypt, Portugal and Spain.
In 1793, the 11th Light Dragoons joined an expedition to help the Dutch against France. In 1801 troops, including a detachment of the 11th, were sent to drive a French army out of Egypt, where they fought at the Battle of Alexandria and were awarded the sphinx as a battle honour.
In 1808 the 10th Light Dragoons sailed to the Peninsula to assist Spain and Portugal after a French invasion, and fought at the battles of Sahagun and Benevente. In 1811 the 10th and 11th Light Dragoons both returned to Spain with Wellington, for a successful campaign.