It means ‘defend, guard’ and is written Wai in Cantonese.
The character 衞 is traditionally preferred although 衛 is now more prevalent, with 卫 being the simplified form in Mainland China.
In 2013 it was found to be the 214th most common surname, shared by 480,000 people or 0.036% of the population, with the province with the most being Shanxi.
[1] During the Zhou dynasty, Wey (衛) ruler Wei Yang (衛鞅)'s family name was Gongsun (公孫), not Wéi family (衛).
[citation needed] During the Han dynasty, Wei Man (衛滿) was baron of Yan (state).