Lars Svenonius (June 16, 1927, Skellefteå – September 27, 2010, Silver Spring, Maryland) was a Swedish logician and philosopher.
He retired in 2009, but was awarded the position of emeritus professor, and continued to teach courses and advise students until his death at 83 years of age.
This field was the object of intense study and saw great progress in the 1950s, largely due to the work of Alfred Tarski and his students at the University of California, Berkeley.
Svenonius' reputation as a mathematical model theorist was established with the publication of three papers in Theoria in 1959 and 1960: In particular, paper (2) contains what is now called "Svenonius' Theorem", an important result on definability of predicates in first order theories.
Presumably as a result of these papers he was named a visiting associate professor at The University of California, Berkeley, for 1962–1963, and gave an Invited Address at the International Symposium on the Theory of Models held there in 1963.