*Termination and Complexity Competition 2021* http://www.termination-portal.org/wiki/Termination_Competition_2021 *Call for Participation* Since the beginning of the millennium, many research groups developed tools for fully automated termination and complexity analysis. After a tool demonstration at the 2003 Termination Workshop in Valencia, the community decided to start an annual termination competition to spur the development of tools and termination techniques. The termination and complexity competition focuses on automated termination and complexity analysis for all kinds of programming paradigms, including categories for term rewriting, imperative programming, logic programming, and functional programming. In all categories, we also welcome the participation of tools providing certifiable proofs. The goal of the termination and complexity competition is to demonstrate the power of the leading tools in each of these areas. The competition will be affiliated to CADE 2021 (http://www.cade-28.info/). The competition will be run on the StarExec platform ( https://www.starexec.org/) shortly before CADE. We strongly encourage all developers of termination and complexity analysis tools to participate in the competition. We also welcome the submission of termination and complexity problems, especially problems that come from applications. A category is only run in the competition if there are at least 2 participants and at least 40 examples for this category in the underlying termination problem data base. If there is no category that is convenient for your tool, you can contact the organizers, since other categories can be considered as well if enough participants are guaranteed. For further information, we refer to the website of the termination and complexity competition: http://www.termination-portal.org/wiki/Termination_Competition_2021 *Important dates* - Tool and Problem Submission: June 30, 2021 - First Run: July 1, 2021 - Bug/Conflict Report Deadline: July 5, 2021 - Bugfix Deadline: July 10, 2021 - Final Run: July 13, 2021 - Presentation of Results: July 15, 2021