The idea that People’s Republic of China (PRC) had a hand in the Thirtieth of September Movement (G30S) has been around since late 1965, and reinforced with unproven accusations and widespread “official” propaganda. However, it has been impossible to prove the involvement of the PRC due to the inaccessibility of related PRC documents. Now, a close reading of the PRC’s archival materials (some of which are again no longer accessible) shows that Beijing’s actual influence over the Communist Party of Indonesia (PKI) and the turn of events in Indonesia in 1965 was far more limited than what the Suharto regime and some scholars have previously claimed. While this article presents new, solid evidence confirming that PKI chairman D. N. Aidit was a willing participant in G30S, and that Mao Zedong knew about this in advance, there is no direct evidence that shows PRC involvement in the planning or actual events. This article addresses the alleged Chinese involvement by first recalling the events leading up to October 1, 1965, and sketching out the development of bilateral relations between Beijing and Jakarta in the early 1960s. Then it proceeds to discuss four issues: Beijing’s military aid to Indonesia’s Fifth Force, the potential transfer of nuclear materials and technology from China to Indonesia, Chinese medical aid to the ailing President Sukarno, and the connection between the Chinese Communist Party and the PKI.