The widespread use and increasing complexity of mission- and safety-critical systems require advanced techniques that address their specification, verification, validation, and certification. The NASA Formal Methods Symposium is a forum for theoreticians and practitioners from academia, industry, and government, with the goals of identifying challenges and providing solutions to achieving assurance in mission- and safety-critical systems. The focus of the symposium is on formal methods, and aims to foster collaboration between NASA researchers and engineers and the wider aerospace and academic formal methods communities. Approaches do not need to directly address the aerospace domain since solutions often are applicable across domains.