Élisabeth Gassiat (née Granier, born 1961) is a French mathematical statistician whose research interests include maximum likelihood estimation for mixture models, latent variables, high-dimensional structured data, the relation between statistics and coding theory, and the statistics of sequence data over finite alphabets. She is a professor at Paris-Sud University.
Gassiat was born in 1961 in Paris. She was a student at the École polytechnique from 1980 to 1983. In 1987 she completed a Ph.D. through Paris-Sud University with the dissertation Blind deconvolution supervised by Didier Dacunha-Castelle.
After serving as an assistant at the Institut national agronomique Paris Grignon from 1987 to 1988, she became an assistant professor at Paris-Sud University from 1988 to 1993. From 1993 to 1998 she was a professor at the University of Évry Val d'Essonne. She returned to Paris-Sud University in 1998, taking her present position as a professor there.
Gassiat became a senior member of the Institut Universitaire de France in 2020. She was named a knight of the Legion of Honour in 2013, and an officer of the Legion of Honour in 2023.
A three-day conference in honor of Gassiat's 62nd birthday was held at the Institut de Mathématique d'Orsay in 2023.
Gassiat is the author of the book Universal Coding and Order Identification by Model Selection Methods (Springer Monographs in Mathematics, 2018, translated by Anna Ben-Hamou from a 2014 French edition).