This book constitutes the refereed proceedings of the 28th Brazilian Symposium on Formal Methods: Foundations and Applications, SBMF 2025, held in Recife, Brazil, during December 3–5, 2025. The 12 full papers and 1 short paper included in this book were carefully reviewed and selected from 24 submissions. They were organized in topical sections as follows: Process Algebras and Time; Formal Verification; Testing; Availability and Contracts; Formal Methods and AI; and Teaching and Foundations.