Proceedings of the Seventh International Conference on Applied Category Theory, held at the University of Oxford on 17 - 21 June 2024. The contributions to ACT 2024 ranged from pure to applied and included contributions in a wide range of disciplines in science and engineering. ACT 2024 included talks in classical mechanics, quantum physics, probability theory, linguistics, decision theory, machine learning, epidemiology, thermodynamics, engineering, and logic.