The Guoqing Temple (simplified Chinese: 国清寺; traditional Chinese: 國清寺; pinyin: Guóqīng sì; Wade–Giles: Kuo-ch'ing Ssu, "Monastery of National Purity") is a Buddhist temple on Mount Tiantai, in Taizhou, Zhejiang Province, China. Originally built in 598 CE during the Sui dynasty, and renovated during the reign of the Qing Yongzheng Emperor (r. 1722–1735), the temple is located roughly 220 kilometres (140 mi) from the city of Hangzhou.

It was the initial site for the creation of the Tiantai school of Mahāyāna Buddhism, founded by the Chinese Buddhist teacher Zhiyi (538–597 CE). The temple covers an area of some 23,000 m² (250,000 sq ft) and features 600 rooms in a total of 14 different halls, including the Mahavira Hall of Sakyamuni, the Hall of Five Hundred Arhats and the Hall of Monk Jigong. The exterior of the building features Chinese pagodas such as the Sui Pagoda, the Seven Buddha Pagoda, and the Memorial Pagoda of Monk Yi Xing (683–727 CE).

In 598 CE, according to Master Zhiyi's last wish, the ruler of Sui dynasty (581–618 CE) built Guoqing Temple on Mount Tiantai. The Tiantai school was one of the first Chinese Buddhist schools to evolve from East Asian Buddhism after it was spread to China. Its founder, the Chinese Buddhist teacher Zhiyi (538–597 CE), lived on Mount Tiantai in Zhejiang for a long time—hence the name of the Tiantai school.

Under the Tang dynasty (618–907 CE), a large number of Japanese diplomats came to China. In the second year of the Zhenyuan Period (804 CE), the eminent Japanese Buddhist monk Saichō came with the diplomats. He studied the Tiantai doctrines in Guoqing Temple on Mount Tiantai introduced by Lu Chun, prefectural governor of Ningbo, Zhejiang. One year later, Saichō returned to Japan where he founded the Tendai school, based on the Tiantai teachings. Since then, the Guoqing Temple has been regarded as the cradle of the Tendai school in Japan.

In 1972, in order to restore diplomatic relations between China and Japan, the Japanese Prime Minister Kakuei Tanaka paid a visit to the People's Republic of China to which the Chinese government attached great importance and made proper arrangements.

During Tanaka's visit, he proposed a personal request to Prime Minister Zhou Enlai to worship at Guoqing Temple, as it was the ancestral temple of Tendai Buddhism in Japan. Tanaka's mother was a devout Buddhist from the Tendai school, who, before he visited China, had asked him to pay homage in the Guoqing Temple on her behalf.

After Tanaka's request, Zhou made inquiries to the relevant departments of Zhejiang province. However, he was told that the Guoqing Temple was unable to receive the Japanese guest at that time as it had not been repaired for many years. Tanaka was informed that Guoqing Temple was being renovated and that he would receive an invitation after it was completed.

Zhou Enlai ordered the renovation plan for Guoqing Temple almost immediately after the visit and stipulated that the temple was to be renovated by 1975. After receiving the notification document, the government of Tiantai County immediately established the Tiantai County Guoqing Temple Restoration Committee.