This volume contains the papers presented at the 13th International Workshop on Logical Frameworks and Meta Languages: Theory and Practice (LFMTP'18) held on July 7, 2018, in Oxford, UK. The workshop was affiliated with the 3rd International Conference on Formal Structures for Computation and Deduction (FSCD) within the 7th Federated Logic Conference (FLoC).

Logical frameworks and meta-languages form a common substrate for representing, implementing and reasoning about a wide variety of deductive systems of interest in logic and computer science. Their design, implementation and their use in reasoning tasks, ranging from the correctness of software to the properties of formal systems, have been the focus of considerable research over the last two decades. This workshop brought together designers, implementors and practitioners to discuss various aspects impinging on the structure and utility of logical frameworks, including the treatment of variable binding, inductive and co-inductive reasoning techniques and the expressiveness and lucidity of the  reasoning process.

We received 13 submissions in total, which were reviewed by at least 3 program committee members or external reviewers. Out of those, 4 were selected for presentation and 4 were selected for presentation and publication in EPTCS. These proceedings include all of them plus one invited submission.

In addition to the submission presentations, the program included 3 invited talks by Delia Kesner (IRIF, CNRS and Université Paris Diderot, France), Kuen-Bang Hou (Favonia) (Institute for Advanced Study, Princeton, USA), and Grigore Rosu (University of Illinois at Urbana-Champaign, USA).

Many people have contributed to the success of LFMTP'18. We would like to thank the organization of FLoC for providing the infrastructure and coordination with other events. We are grateful for the great program committee who submitted all reviews on time and participated actively on the decisions. The authors and invited speakers are the ones responsible for a very interesting program, and the attendees for fruitful and stimulating discussions.