Explore the Family Name Guillermo

The meaning of Guillermo

Spanish: from the personal name Guillermo, an equivalent of William. Some characteristic forenames: Spanish Juan, Jose, Julio, Luis, Amador, Carlos, Claudio, Emeterio, Eugenio, Lopez, Luz, Margarita.

Dictionary of American Family Names, 2nd edition, © Oxford University Press, 2022.

How common is the last name Guillermo in the United States?

The popularity of the surname Guillermo has seen a significant increase from the year 2000 to 2010, according to data from the Decennial U.S. Census. The ranking of the surname Guillermo improved by approximately 17.74%, moving up from 11,647 in 2000 to 9,581 in 2010. Furthermore, the count of individuals with the surname Guillermo increased by 37.42% from 2,469 in 2000 to 3,393 in 2010. This growth is reflected in the proportion per 100k residents, which saw a 25% increase from 0.92 in 2000 to 1.15 in 2010.

	2000	2010	Change
Rank	#11,647	#9,581	17.74%
Count	2,469	3,393	37.42%
Proportion per 100k	0.92	1.15	25%

Race and Ethnicity of people with the last name Guillermo

In terms of ethnic identity, the Decennial U.S. Census data shows various shifts between 2000 and 2010. The largest group identifying as Guillermo are those of Hispanic ethnicity, which increased by 6.73% from 51.56% in 2000 to 55.03% in 2010. The second most common ethnic identity, Asian/Pacific Islander, saw a decrease of 8.35% during this period. There were also changes among other ethnicities. Those identifying as of two or more races saw an increase of 7.65%, while there was a slight increase of 0.46% in people of White ethnicity. The Black demographic saw a sharp decrease of 40.37%, and the American Indian and Alaskan Native category declined by 33.33%.

	2000	2010	Change
Hispanic	51.56%	55.03%	6.73%
Asian/Pacific Islander	38.56%	35.34%	-8.35%
White	4.37%	4.39%	0.46%
Two or More Races	4.05%	4.36%	7.65%
Black	1.09%	0.65%	-40.37%
American Indian and Alaskan Native	0.36%	0.24%	-33.33%