This book constitutes the refereed proceedings of the 14th International Symposium on Frontiers of Combining Systems, FroCoS 2023, held in Prague, Czech Republic, in September 2023. The symposium was co-located with the 32nd International Conference on Automated Reasoning with Analytic Tableaux and Related Methods, TABLEAUX 2023. The 14 papers presented were thorouhgly reviewed and selected from the 22 high-quality paper submissions. They are grouped in the volume according to the following topic classification: analysis of programs and equations; unification; decidable fragments; frameworks; higher-order theorem proving. This is an open access book.