With a permanent population of only around 800 people, only a select few surnames in Vatican City are shared by more than one individual. Those include Bachmann and Graf, which are the most popular last names in the Vatican, followed by Merga. Otherwise, most individuals who live in the Vatican have a unique last name.

Seven countries share Ali as their most common surname: the United Arab Emirates, Kuwait, Bahrain, Somalia, Libya, Eritrea, and Oman. These majority Muslim nations took the popular last name from the religious leader Ali, the cousin and son-in-law of the prophet Muhammad and one of the central figures in Shia Islam. Despite its dominance in those seven countries, most of the world's Alis actually live in Pakistan, where the surname comes second in popularity to Khan.

In Papua New Guinea, the most common last names are all thought of as first names in most of the rest of the world. John, Peter, Paul, David, and James top the biblical list, which continues with the names Thomas, Joseph, Simon, Philip, and Andrew. It takes 26 Papua New Guinean surnames before one is found that isn't also a common first name in the West — the 27th most-common last name is Kaupa.

From the Indigenous Aymara word meaning "glass" or "precious stone," Quispe is the most common last name in Peru. Approximately 1 in 55 Peruvians share the surname, making it far more common than Garcia, Gonzalez, or Rodriguez — which are names of Spanish origin that dominate much of the rest of the continent.

Jamaica and the United States share many of their most common surnames. The fourth-most popular last name in the United States is Jamaica's top name: Brown. Following that, Jamaicans prefer names such as Williams, Smith, Campbell, and Johnson — echoing many of the top names in the U.K. and the U.S.

The total population of the small island nation of Mauritius is roughly 1.2 million — about 7,000 of whom share the country's most common last name: Beeharry. The name comes from the Sanskrit word "vihara," meaning "one who roams about for pleasure,” and was anglicized during the country's British colonial rule from 1810 to 1968.

Surnames such as Ganbold, Ganbaatar, and Batbayar are found almost exclusively within the borders of Mongolia. Per 2014 estimates, about 22,000 Ganbolds lived in Mongolia, compared to just 80 in the United States, though the U.S. was home to the second largest number of Ganbolds anywhere. A similarly small number of Ganbolds have also emigrated to neighboring Russia.

More common than Weber, Meyer, Fischer, Schneider, and Schmidt is the German surname Müller, which is analogous to Miller in English. More than 1% of the German population shares the last name, which is also the most common in Switzerland, Germany's neighbor to the south.

With more than 77,000 Irish Murphys, the name is the most popular surname on the Emerald Isle. Popular across Ireland, particularly in County Cork, Murphy comes from the ancient Irish names "Ó Murchadha" and "Ó Murchadh," which are said to mean "sea-warrior." It has been the most common last name in Ireland for more than 100 years.

Ei, the second-most common last name in Myanmar, is the most common last name in the world to start with the letter "E." With just over 1.2 million Eis in the world, it is the 418th-most common last name.

The name Silva comes from several place names on the Iberian Peninsula in Spain and Portugal, and means "thicket of briars" or "woods” in Portuguese. It is the most common surname in Portugal and, due to colonization, its variant "Da Silva" is the most common in Brazil.

Cohen — translating in Hebrew to “priest” — is by far the most popular surname in Israel. While there are nearly as many Cohens in the United States as there are in Israel, they make up a more substantial portion of the total Israeli population, given the Middle Eastern country’s smaller size. Levy and Mizrahi are also popular Israeli surnames.

Devi, the most common surname in India and sixth-most common in the world, comes from a Sanskrit word meaning "goddess" and is often chosen by women to become their last name after they marry. More than 70 million people share the surname, accounting for roughly one in every 11 Indian citizens.

While most of Canada is English-speaking, the sole official language of the province of Quebec is French, reflecting the region’s French colonial heritage. Surnames of French origin — such as Tremblay, Gagnon, and Roy — are more prevalent there than in any other Canadian province. In other provinces like Ontario, English surnames such as Smith, Brown, and Wilson dominate.

Hernandez is the most common last name in Mexico, followed by Garcia, which is the only surname in the top 10 not to end in “z.” Rounding out the list are the names Martinez, Lopez, Gonzalez, Perez, Rodriguez, Sanchez, Ramirez, and Cruz.

With upwards of 1.6 million Garcias on the continent, the surname trounces Martin, Müller, and Rodriguez as the most popular European last name. As you might expect, the majority of European Garcias live in Spain, though the next largest number of people with that surname reside in neighboring France — followed by England, Belgium, and Switzerland.

Vietnamese people have been using last names since 111 BCE when the country was under control of China during the Han Dynasty. At the time, the Chinese empire was just beginning to assign people last names, so the most likely scenario is that a Chinese official gave all the people in its newly conquered Vietnamese territory the same last name. The name was Ruan, which became Nguyen over the centuries. It is still used by nearly 40% of Vietnamese people.

Australia, New Zealand, the United Kingdom, and Canada all share the same top last name as the United States: Smith. The name, which refers to the historic profession of blacksmithing, originated in England and spread during the expansion of the British Empire. The name's popularity may be waning, however. In 2020, newborn babies in New Zealand were most commonly born with a different last name: Singh.

Kim is the most popular surname in both North Korea and South Korea, with nearly a quarter of the Korean Peninsula's population sharing the name. It comes from the Chinese character meaning gold or metal, and its popularity in Asia makes it the 25th-most common last name in the world.

Wang, meaning "king" in Chinese, is the most common last name in the world's most populous country. Worldwide, more than 100 million people go by the surname Wang, accounting for one out of every 68 people on Earth. Many of the most popular last names come from China, and 40% of the country's citizens use the last names Wang, Li, Zhang, Liu, Chen, Yang, Huang, Zhao, Zhou, or Wu.