Manuel Alvar (July 8, 1923 – August 13, 2001) was a Spanish linguist, historian, and university professor who specialized in the study of dialectology and philology of the Spanish language. Throughout his career, Alvar oversaw and influenced the creation of many Spanish linguistic atlases; maps which recorded speech variations in a given geographical area. He served as Director of the Real Academia Española for four years and was a member of language academies throughout Europe and Latin America.

Manuel Alvar was born on July 8, 1923, in Benicarló, Castellón de la Plana, Spain. He began his studies at the Universidad de Zaragoza, where he was a student of José Manuel Blecua, a renowned Spanish philologist. Alvar transferred to the Universidad de Salamanca and graduated from there in 1945 with the highest honors, with a degree in Philosophy and Spanish Literature. Just three years later, Alvar received his doctorate from the Universidad de Madrid. His primary teaching position was at the Universidad Autónoma de Madrid.

Alvar married historian Elena Ezquerra and together they had seven sons, many of whom are likewise academics and linguistically inclined—one is a lexicographer and university linguistics professor; another teaches Romance language philology; a third teaches Latin philology.

Alvar lost his battle to lung cancer in August 2001, at the age of 78. He is buried in Chinchón, a small town southeast of Madrid.

Alvar's research provides sociohistorical context of Spanish dialect diversification, outlined in his Manual de dialectología hispánica (1996). His studies cover Spanish dialect variants in his native country (especially in Andalucía, the Canary Islands, Navarra and Aragón regions), as well as Spanish dialects in the United States, South and Central America. Alvar's study of Spanish in the Aragón region includes an in-depth historical background, development of orthography over time, personal names, and variation in syntax, morphology, and phonology, published in his 1953 work El Dialecto Aragonés.

For Alvar's later publication, "Atlas lingüístico y etnográfico de Aragón" (1979-1983), he and his team transcribed words pronounced in isolation, elicited from residents of the Aragón region. He used a similar method to elicit data from people living in the Canary Islands and published a linguistic atlas of this dialect in 1975. Alvar was a strong proponent of smaller linguistic atlases focusing on regional variation rather than larger national atlases—his Atlas Lingüístico de España y Portugal reflects this preference, though that atlas began more than 30 years ago with the fieldwork still not complete. Alvar has also been criticized for using overly traditional field methods in his dialectology studies, for example focusing on forms in isolation rather than in context, or leaving out morphosyntactic variables.

Alvar spent much of his professional life teaching. He began his teaching career in 1947 at the University of Salamanca as an adjunct professor. In 1948 he became chair of the department of Spanish languages at the University of Granada. Alvar also taught at the Autonomous University of Madrid and Universidad Complutense, securing chair positions at both universities in 1968 and 1971, respectively. He served as director of a program teaching Spanish language and culture to foreigners in Málaga from 1965 to 1968, and was known for his passion for teaching Spanish as a foreign language throughout his life. In 1966, Alvar developed an advanced Spanish philology course at the Spanish National Research Council (CSIC), leading it until 1997.

He served as a visiting professor at universities in his native Spain as well as many foreign universities, and was nominated for awards at several universities in North and South America, as well as Europe.