A Moscow court backed a request by Russia's justice ministry, which said Golos was not in compliance with the law and the NGO has been engaged in political activities, Interfax reported.
"We will obviously appeal this decision," Golos' lawyer Maxime Kroupski told the Russian news agency, saying the dissolution order was illegal.
"The ministry discovered these violations in September 2015 and ordered us to remedy them before November 20," he said. "Therefore, the law has not been broken."
The penalty is believed to be the largest ever imposed on a Russian organisation for violating the notorious law and comes ahead of parliamentary polls in September.
NGOs say the legislation, which requires organisations that receive overseas funding and engage in political activity to register as "foreign agents," undermines them and aims to crack down on civil society.
Many have not complied and Golos, which monitored local and national elections with the backing of Western money, ceased its operations in 2013.
Golos has exposed numerous violations in the past, including the 2011 election won by the ruling party and the presidential vote the following year that saw Vladimir Putin return to the Kremlin.
September's legislative elections come against a backdrop of economic crisis in Russia.
