Kaur (Punjabi: ਕੌਰ) in Sikhism (meaning: "Princess") is a mandatory last name for all baptized female Sikhs. However, it is often used as a middle name. Apart from Sikhs, it is also used as a surname by Hindu Jat and Rajput women.
Kaur is a name used by Sikh women either as the middle name, or as a last name. It can be regarded as a true surname. The tenth guru of Sikhs, Guru Gobind Singh, made it mandatory for Sikh females to use the name Kaur and for Sikh males to use the name Singh, when he administered Amrit (baptism) to both males and female Sikhs. All female Sikhs were asked to use the name Kaur after their forename and males were to use the name Singh. (Since 'Kaur' means "Princess", the name acts as a symbol of equality among males and females.) This custom further confirmed the equality of both genders as was the tradition set by the founder of Sikhism, Shri Guru Nanak Dev Ji. It was intended to give women a sense of self-respect. Singh is also used by some females because Singh can be a last name. It is the most common last name used by Sikhs.
Kaur provides Sikh women with a status equal to all men. This was also intended to reduce the prejudice created by caste-typing based on the family name. Prejudice based on caste was still rampant during Guru Gobind's time (17th century). This particularly affected women who were expected to take their husband's family name upon marriage. The British required women to take on their husbands' names.
Sikh principles believe that all men and women are completely equal. Therefore, a woman is a princess and can lead her own life as an individual, equal to men. She does not need a man's title to raise her own status. Saying this would go against the principles stated in the Sri Guru Granth Sahib, the religious text of Sikhism. Guru Nanak Dev Ji states:
Also, Gurbani (the text from Guru Granth Sahib) addresses to every individual (irrespective of gender) as a female. And combining from the above defined excerpt from Guru Granth Sahib  it can be easily concluded the temporal status of woman is higher than of man and they are equal only spiritually.
Immigration issues: Common surname
A section of around a million adherents of Sikhism who live abroad in western countries keep only Singh or Kaur as their last name. This has caused legal problems in immigration procedures, especially in Canada with the Canadian High Commission in New Delhi, India for a decade stating in letters to its Sikh applicants that "the names Kaur and Singh do not qualify for the purpose of immigration to Canada." People with these common Sikh surnames had to change their last names before coming to Canada. This had been causing emotional, legal and financial hardship for Sikh applicants in India who were complying by undergoing costly and lengthy name change procedures out of fear that their application to immigrate to Canada would be rejected outright otherwise. However as soon as the media got involved and after a storm of complaints from Sikhs, Citizenship and Immigration Canada, Ottawa reversed New Delhi office's 10-year decree with Canadian Federal immigration officials further clarifying that "asking applicants to provide a surname in addition to Singh or Kaur has been an administrative practice used by our visa office in New Delhi as a way to improve client service and reduce incidents of mistaken identity. This was not a mandatory requirement. There is no policy or practice whereby people with these surnames are asked to change their names, the letters that were sent out to Sikh clients in Delhi were poorly worded."
- The Sikhs by Khushwant Singh[page needed]
- Dr. McCleod, Head of Sikh Studies, Department of South Asian Studies, McMaster University, Hamilton, Ontario, Canada
- Khushwant Singh, A History of the Sikhs, Volume I
- Guru Granth Sahib, page 473
- Common Sikh names banned under Canada's immigration policy; July 23, 2007; CBC News; Canada,  Speaking Notes: Statement from the Minister of Citizenship and Immigration on Surnames on Permanent Resident Applications; Ottawa, Ontario, Canada; July 26, 2007, Sikh name-change letter 'poorly worded': Immigration Canada; July 25, 2007; CBC News; Canada, Sikh group slams immigration name change policy; July 25, 2007; CBC News; Canada, Tune that name, In Depth Immigration; July 25, 2007; By Georgie Binks CBC News; Canada, Letter to CBCNews.ca from Citizenship and Immigration Canada, Clarifying the names policy; In Depth Immigration; July 26, 2007; CBC News; Canada, Common surnames, In Depth Immigration; July 26, 2007; CBC News; Canada, FBI Name Check Cited In Naturalization Delays (USA), Official Calls Backlog 'Unacceptable'; June 17, 2007; By Spencer S. Hsu and N.C. Aizenman; Washington Post Staff Writers, No more Singhs, Kaurs on visa forms: Canada; 26 Jul 2007; The Times of India
- WHAT THE LETTER SAYS: 'Singh' ban denounced, After a storm of complaints from Sikhs, Ottawa reverses New Delhi office's 10-year decree that `the names Kaur and Singh do not qualify for the purpose of immigration to Canada'; Jul 26, 2007; By San Grewal Staff reporter, TheStar.com, Canada, Canada allows Sikhs to keep last names; Jul 26, 2007; USA TODAY, Canada drops immigration policy on Sikh surname; 26 Jul 2007; The Times of India
- Khushwant Singh, History of Sikhs: 1469-1838, Vol I, Oxford University Press, 2004, page 80, footnote 14.