Kuwaiti authorities have said rallies must receive written permission as part of efforts to quell growing unrest over last month's parliamentary elections.
But organizers of Sunday's protest used social media to mobilize crowds.
Opposition groups have accused Kuwait's ruler of overstepping his powers by changing voting rules that appeared to favor government critics, which span from Islamist factions and pro-reform liberals. They now seek to bring down the new parliament dominated by pro-government lawmakers.
Kuwaiti rights activist Mohammed Al-Humaidi says several protesters were arrested. There were no immediate reports of injuries.