Erzhu Tianguang (simplified Chinese: 尔朱天光; traditional Chinese: 爾朱天光; pinyin: Ěrzhū Tiānguāng) (496–532) was a general of the Chinese/Xianbei dynasty Northern Wei. He became a major general during the reign of Emperor Xiaozhuang, when his father's cousin Erzhu Rong was the paramount general of the state. He was renowned for pacifying the Guanzhong region, which had been seized by agrarian rebel generals Moqi Chounu (万俟醜奴) and Wang Qingyun (王慶雲) in 530. He thereafter tried to maintain a relatively distant profile from the other Erzhu clan members, particularly after Emperor Xiaozhuang killed Erzhu Rong later in 530 and then was overthrown and killed by Erzhu Rong's nephew Erzhu Zhao and cousin Erzhu Shilong. In 532, after the other Erzhus had suffered defeats at the hand of the rebelling general Gao Huan, Erzhu Tianguang tried to come to their aid, but was also defeated by another general who rebelled, Husi Chun, and Gao executed him.
Erzhu Tianguang's father was a cousin of Erzhu Rong, who was a Northern Wei general and the chief of the ethnic Xiongnu Qihu (契胡) tribe. In Erzhu Tianguang's youth, he was described to be resolute and capable in archery and horseriding. Erzhu Rong considered him a close confidant, and often discussed military matters with him. In 528, after Emperor Xiaoming was poisoned by his mother Empress Dowager Hu, it was after consulting with Erzhu Tianguang that Erzhu Rong set out to attack the capital Luoyang to overthrow Empress Dowager Hu. As he did, he entrusted one of his home provinces, Si Province (肆州, roughly modern Xinzhou, Shanxi) to Erzhu Tianguang, and after Erzhu Rong killed Empress Dowager Hu and made Emperor Xiaozhuang emperor, Erzhu Tianguang was created the Duke of Chang'an. In 528, when Erzhu Rong set out to destroy the rebel Emperor of Qi, Ge Rong (葛榮), he entrusted his entire home base, including Bing Province (并州, roughly modern Taiyuan, Shanxi) to Erzhu Tianguang as well, remarking, "Only you can make me feel secure about places where I am not at."