Guo Zhongshu (c. 929 – 977), courtesy name Shuxian (or Guobao, according to Xuanhe Huapu), was a Chinese calligrapher, painter, philologist, and scholar during the Five Dynasties period and Song dynasty. He was noted for his paintings of landscapes and structures.

Early in his career, Guo Zhongshu served under the Later Han governor Liu Yun until Liu was murdered by the usurper Guo Wei. He later served in the Later Zhou and Song imperial governments, but was banished multiple times for behavioral problems. Especially in his later life, he was known for his eccentricity. Su Shi's eulogy as well as later anecdotes celebrated his apparent free spirit, wit, courage, and egalitarian tendencies. Alexander Soper, however, saw symptoms of schizophrenia which he blamed for Guo's death.

Guo Zhongshu was from Luoyang, while his ancestral home was in Shanghe County. A child prodigy, at the age of 6 he could already recite Confucian classics and compose essays, and that year he passed the Later Tang dynasty's national children's examination (童子科). (The exam was for children under 15 who could recite Classics and compose poetry in both the shi and fu forms, recommended by the prefect and personally tested by the emperor.) He was also good at calligraphy, especially the seal script and the large seal script. Once, when shown a manuscript in the rare bird seal script, he was so absorbed by it that he read and copied it overnight.

During the Later Han dynasty, Liu Yun—a cousin of the Later Han emperor Liu Chengyou—was named the military governor of Wuning Circuit (武寧, headquartered in Xu Prefecture) in 948. Guo Zhongshu, who was around 19 at that time, went to Xu Prefecture and served as a prefectural judge (推官) under him.

In late 950, military governor Guo Wei rebelled and quickly captured the capital Daliang (also known as Kaifeng). Emperor Liu Chengyou was killed on 2 January 951. With Guo Wei's ostensible consent, the widowed Empress Dowager Li (Liu Chengyou's mother) chose Liu Yun to succeed the throne. On 4 January, senior official Feng Dao was sent with her edict to Xu Prefecture to escort Liu Yun back to the capital. After Feng Dao's arrival, Liu Yun took most of his retinue (including Guo Zhongshu) and set out for Daliang—but he wouldn't make it, because Guo Wei having consolidated enough power in Daliang was no longer satisfied with remaining a mere subject. On 30 January, supported by thousands of his soldiers who made a (likely orchestrated) commotion, Guo Wei agreed to ascend the throne, and immediately, General Guo Chongwei was sent with 700 cavalries to intercept Liu Yun, who had by then arrived in Song Prefecture. When Guo Chongwei came to Song Prefecture, he first met with Feng Dao outside the city gate before venturing inside to meet with Liu Yun. Realizing this is a conspiracy, the 22-year-old Guo Zhongshu angrily lambasted the 69-year-old Feng Dao, who had disloyally held high positions under the Later Tang, Later Jin, and the Liao dynasty before Later Han:

Sir, you have been an important minister during many dynasties. Your honesty and integrity is renowned in the world. Even those who lack virtues respect you as an elderly gentleman. If you go back on your word and betray the Han dynasty today, you will be throwing away all you have accomplished in your life. How can you not have any qualms?

Feng Dao was too ashamed to respond. Guo Zhongshu and others then advised Liu Yun to immediately kill Feng Dao, gather the troops in Song Prefecture and flee to Hedong Circuit where Liu Yun's father Liu Chong was stationed as the military governor. Liu Yun hesitated (because Guo Chongwei said Guo Wei had nothing but good intentions), but by the next morning everything was already too late—Guo Chongwei had secretly taken control of his guards the night before and put him under house arrest. Guo Zhongshu fled to the "mountains and wilderness", and in less than a month Guo Wei founded the Later Zhou dynasty and had Liu Yun murdered.

(Su Shi's eulogy (included in his Dongpo Ji 東坡集) offers a different account. It states that Guo Zhongshu resigned from his post before 950, following a quarrel with Dong Yi (董裔), a staff supervisor (判官).)