The conference participants were to include the former Russian oligarch Mikhail Khodorkovsky, members of Russian punk protest band Pussy Riot, and Wikipedia founder Jimmy Wales.
"Urgent: a Norwegian hotel strike has forced us to cancel the 2014 Oslo Freedom Forum," the events organizers announced over Twitter on Friday. "We are devastated and heartbroken."
According to Norway's NTB newswire the Grand Hotel in Oslo, where the event was to take place, decided that an upcoming strike of hotel workers meant it would no longer be able to host it.
The organizers plan to reschedule the event for October.