Lia Bronsard (b. 1963) is a Canadian mathematician, the 2010 winner of the Krieger–Nelson Prize and the former president of the Canadian Mathematical Society. She is a professor of mathematics at McMaster University. In her research, she has used geometric flows to model the interface dynamics of reaction–diffusion systems. Other topics in her research include pattern formation, grain boundaries, and vortices in superfluids.
Bronsard is originally from Québec, where she was born in 1963. She did her undergraduate studies at the Université de Montréal, graduating in 1983, and earned her PhD in 1988 from New York University under the supervision of Robert V. Kohn. After short-term positions at Brown University, the Institute for Advanced Study, and Carnegie Mellon University, she moved to McMaster in 1992. She was president of the Canadian Mathematical Society for 2014–2016.