Demonstrators near the government headquarters in Chisinau waved flags and listened to speeches delivered amid chants of "We are the People".
Some were holding icons and carrying white flowers as a sign of peaceful protest.
"Ambassadors (of the US and the EU) and partners in development, the great people of Moldova want only one thing: to orchestrate the political parties on a snap election. This is a common goal that has united us and this is what we expect from you - do not support the mafia, support the people of Moldova," said Vasile Nastase, chairman of the civic group Dignity and Truth, as he addressed the rally.
Radio Free Europe/Radio Liberty (RFE/RL) quoted police as saying that some 16,000 people came to the rally.