Princess Xincheng
| Unknown | |
|---|---|
| Princess Xincheng | |
| Born | 634 |
| Died | 663 |
| Spouse | Zhangsun Quan Wei Zhengju |
| Father | Emperor Taizong of Tang |
| Mother | Empress Zhangsun |
Princess Xincheng (新城公主; 634–663), formerly titled Princess Hengshan, was a royal princess of the Tang dynasty. Her personal name was not recorded. She was the youngest child of Emperor Taizong of Tang and Empress Zhangsun, making her the full younger sister of Emperor Gaozong.
Princess Xincheng was first married to Zhangsun Quan of Henan, a member of the imperial Zhangsun clan. Following his death, she remarried Wei Zhengju of Jingzhao.