The Sixth International Conference on Applied Category Theory took place at the University of Maryland, 31 July -- 4 August 2023. This conference follows the previous meetings at Leiden (2018), Oxford (2019), MIT (2020, fully online), Cambridge (2021) and Glasgow (2022). The conference comprised contributed talks, a poster session, an industry showcase session, and a session where junior researchers who had attended the Adjoint School presented the results of their research at the school. Information regarding the conference may be found at (https://act2023.github.io/). The contributions to ACT2023 ranged from pure to applied and included contributions in a wide range of disciplines in science and engineering. Submission to ACT 2023 had three tracks: extended abstracts, software demonstrations, and proceedings. Only papers submitted to the proceedings track were considered for publication in this volume.

翻译：第六届应用范畴论国际会议于2023年7月31日至8月4日在马里兰大学举行。本次会议延续了此前在莱顿（2018）、牛津（2019）、麻省理工学院（2020，全线上）、剑桥（2021）及格拉斯哥（2022）举办的系列会议。会议内容包括专题报告、海报展示、工业案例展示专场，以及由参与"Adjunction School"的青年研究人员汇报其研究成果的专场。会议相关信息可查阅（https://act2023.github.io/）。ACT2023的投稿涵盖从纯理论到应用层面的内容，涉及科学与工程领域的广泛学科。本次会议投稿分为三个类别：扩展摘要、软件演示及正式论文集。仅提交至正式论文集类别的论文被纳入本卷审稿范围。