Sikhs have a given name and one or both of a surname and a Khalsa name. The surname may be a family name (based on the name of the ancestral village, ex. Khaira) or a caste name. Despite that the Guru Granth Sahib prohibits the use of a caste system, different castes still exist today in some aspects of Punjabi culture; unlike the Hindu caste system, however, this system is based on employment (ex. jaat signifies the farming caste).
On becoming a Khalsa (becoming baptized), the Sikh undertakes the obligation to wear the physical symbols of this status (the Five Ks) and takes the name "lion", usually romanized as Singh, if a man, or /kaur/ "princess", usually romanized as Kaur, if a woman. (Note that Singh is spelled irregularly: it is written /singh/ but pronounced /siṅg) These names reflect the strong egalitarianism of the Sikh religion. The adopting of the Khalsa name is symbolic for being a member of a larger family or faith. These names were originally intended to replace the Sikh's original surname, which was often a caste name.
Some Sikhs do replace their original surname with their Khalsa name, but many retain their original surname and add the Khalsa name before it. Thus, a man born Sandeep Brar should become Sandeep Singh but more likely will become Sandeep Singh Brar. Similarly, a woman born Harjeet Gill should become Harjeet Kaur or Harjeet Kaur Gill.
First Names
Sikhs use a set of several hundred given names, all or nearly all meaningful, usually with a religious or moral theme. For example, Ujjal means "bright, clean, holy". The process of choosing a Sikh's first name occurs following the first few days of their birth, in a ceremony called the Hukamnama (referring to a hymn from the Guru Granth Sahib as the will from God); a family often selects a name for a child by opening the Sikh holy scripture, the Guru Granth Sahib to a certain "aang" and choosing a name that begins with the first letter of the first word on the "aang".
Sikh given names are gender neutral, generally formed of a prefix and a suffix (ex. Har/jeet/). There is however, a gender connotation attached when pronouncing a name, say Parkāśh for example; it may be either male or female, but /parakāśō/ is female while /parakāśū/ is male.
Surnames
In Sikhism, women don't change their surnames after marriage - this is due to the fact that each partner keeps Singh and Kaur respectively (with the exception of gender non-conforming and same-sex married Sikhs, who use their preferred names). Again, Punjabi culture generally contradicts this as women are expected to take their husband's family name. Their daughters would then generally have a given name, as well as the Khalsa name and their father's last name, which is usually the name of the father's village; for example, a girl with the name Harjeet, whose father's last name is Aulakh, would then become Harjeet Kaur Aulakh (meaning "Harjeet, princess of Aulakh"). In spite that this system is not permitted for Sikhs as it reinforces both tribalism and the patriarchy, it is the most widely used naming system amongst non-baptized Sikhs (and still prevalent among baptized Sikhs).
Modern Sikh families living in bigger, cosmopolitan cities, have adopted names from other communities as well. For instance, in New Delhi you might find a Sikh girl named simply Amita. In this case, the second name Kaur has been done away with and more significantly, the name Amita is unlike any conventional Sikh first name and is, in fact, a name more commonly associated with a Hindu girl. Some Sikh girls take on last name of Singh, a practice more common in larger cities.
Most Sikhs that still use the sole Singh and Kaur (without any other family name) are commonly baptized. Some believers maintain that this practice of naming without using the word Singh or Kaur is manmat (Against the will of the Guru) and is prohibited in the Rehat Maryada (The way of living of Sikhs).