Police fired tear gas and water cannon on Tuesday at demonstrators outside the Indonesian parliament.
They were among tens of thousands in cities nationwide protesting against proposed new legislation that would ban sex before marriage.
The bill would outlaw most abortions and make insulting the president illegal.
The bill has been delayed, but the protesters, who are mostly students, are concerned it could still eventually pass through parliament.
Despite the delay, many Indonesians are concerned that the bill could still be pushed through parliament.