Charl (Sarel) Arnoldus Cilliers (7 September 1801 – 4 October 1871) was a Voortrekker leader and a preacher. With Andries Pretorius, he led the Boers to a huge victory over the Zulus at the Battle of Blood River in 1838. In particular, Cilliers lead the Voortrekkers in a vow which promised that if God would protect them and deliver the enemy into their hands, they would build a church and commemorate the day of their victory as if it were an annual Sabbath day, which their descendants would also be instructed to honour.