Wang Ya (Chinese: 王涯; died December 17, 835), courtesy name Guangjin (廣津), formally Duke of Dai (代公), was an official of the Chinese Tang dynasty, serving as a chancellor during the reigns of Emperor Xianzong and Emperor Xianzong's grandson Emperor Wenzong. During Emperor Wenzong's reign, he became involved in a major power struggle between imperial officials and eunuchs known as the Ganlu Incident, and he was killed by the eunuchs along with three other chancellors, Li Xun, Jia Su, and Shu Yuanyu.
It is not known what year Wang Ya was born in — although he should have been born sometime between 757 and 765, as he was said to be in his 70s when he eventually died in 835. His family was from the Tang Dynasty northern capital Taiyuan and claimed to be descended from the Northern Wei official Wang Jiong (王冏). His grandfather Wang Zuo (王祚) served as a military advisor to a prefect, while his father Wang Huang (王晃) served as a prefectural prefect. He had at least two older brothers, Wang Zhao (王沼) and Wang Jie (王潔).
In 792, during the reign of Emperor Dezong, Wang Ya passed the imperial examinations in the class of those who used grand speech, and he was made the sheriff of Lantian County (藍田, in modern Xi'an, Shaanxi). In 804, he was made Hanlin Xueshi (翰林學士), an imperial scholar. He thereafter served in the palace, going through the offices of You Shiyi (右拾遺), a low-level consultant at the legislative bureau of government (中書省, Zhongshu Sheng); Zuo Bujue (左補闕), a consultant at the examination bureau (門下省, Menxia Sheng); and Qiju Sheren (起居舍人), an imperial chronicler. After Emperor Dezong died in 805 and was succeeded by his seriously ill son Emperor Shunzong, Wang was one of the imperial scholars who were involved in drafting the edict to create Emperor Shunzong's son Li Chun crown prince, along with Zheng Yin, Wei Cigong (衛次公), and Li Cheng.