The name Nikki is a diminutive form of the Greek name Nikolaos, which is derived from the words "nikan" meaning "to conquer" and "laos" meaning "people." The name Nikolaos was initially used in ancient Greece and later adopted by the Romans. It gained popularity during the Early Christian era, as it was borne by several saints and church figures.

One of the earliest recorded instances of the name Nikki can be found in the Byzantine Empire, where it was a shortened version of the name Nikolaos used as a nickname or pet name. The name spread across Europe during the Middle Ages, particularly in regions with strong Greek and Eastern Orthodox Christian influence.

In the 12th century, the Italian philosopher and theologian Nikolas of Cusa, also known as Nicholas of Cusa (1401-1464), was a prominent figure who bore the name Nikolas. During the Renaissance period, the painter Niccolo Machiavelli (1469-1527) was also known by the diminutive form Nikki.

In the 18th century, the Russian Empress Catherine the Great (1729-1796) had a close friend and confidante named Nikki, whose real name was Nikifor Ivanovich Panin. This helped popularize the name in Russia and other Slavic regions.

The name Nikki gained further recognition in the 19th century with the Russian writer Nikolai Gogol (1809-1852), who is often referred to by the diminutive form Nikki in Russian literature. Another notable figure from this period is the American inventor Nikola Tesla (1856-1943), whose name is a variation of the Serbian form Nikola.

In the 20th century, the name Nikki became increasingly popular in English-speaking countries, particularly as a feminine name. One of the most famous bearers of the name is the American singer and actress Nikki Sixx (born 1958), co-founder of the rock band Mötley Crüe.