Ximen is a Chinese compound surname

Chinese compound surname

A Chinese compound surname is a Chinese surname using more than one character. Many of these surnames derive from noble and official titles, professions, place names and other areas, to serve for a purpose. Some are originally non-Han, while others were created by joining two one-character family...

. Ximen literally means "west gate", the origination story says that there was a noble family in Zheng

Zheng (state)

Zheng （) was a vassal state in China during the Zhou Dynasty located in the centre of ancient China in modern day Henan Province on the North China Plain about east of the royal capital at Luoyang. It was the most powerful of the vassal states at the beginning of the Eastern Zhou...

 or Qi

Qi (state)

Qi was a powerful state during the Spring and Autumn Period and Period of the Warring States in ancient China. Its capital was Linzi, now part of the modern day city of Zibo in Shandong Province....

 state live near the west gate, so the descents took Ximen (west gate) as their family name. Due to compound surnames being rare in China, some Ximen families changed their name to single surname Xi(西).

Notable people named Ximen

• Ximen Bao
  Ximen Bao
  Ximen Bao was an ancient Chinese government minister and court advisor to Marquis Wen of Wei during the Warring States period of China. He was known as an early rationalist, who had the State of Wei abolish by law the inhumane practice of sacrificing people to river deities...
  
  , minister and court advisor in Wei
  Wei (state)
  The State of Wei was a Zhou Dynasty vassal state during the Warring States Period of Chinese history. Its territory lay between the states of Qin and Qi and included parts of modern day Henan, Hebei, Shanxi and Shandong...
  
  
• Ximen Qing, fiction character in Water Margin
  Water Margin
  Water Margin , also known as Outlaws of the Marsh, All Men Are Brothers, Men of the Marshes, or The Marshes of Mount Liang, is one of the Four Great Classical Novels of Chinese literature.Attributed to Shi Nai'an and written in vernacular Chinese, the story, set in the Song Dynasty,...
  
  and The Plum in the Golden Vase
• Ximen Chuixue, fiction character in The Legend of Lu Xiaofeng