This volume contains the proceedings of the 14th International Conference on the Application and Theory of Petri Nets. The aim of the Petri net conferences is to create a forum for discussing progress in the application and theory of Petri nets. The volume includes three invited papers, Modelling and Enactment of Workflow Systems, Interleaving Functional and Performance Structural Analysis of Net Models and FSPNs: Fluid Stochastic Petri Nets, together with 26 full papers (selected from 102 submissions) and 6 project papers.