The 15th International LISA Symposium was hosted by the Relativity Group at University College Dublin on 7th – 12th July 2024. The symposium featured a program dedicated to gravitational wave astrophysics, with particular emphasis on sources that can be observed in the millihertz band by the Laser Interferometer Space Antenna (LISA), the current status and unique challenges in gravitational theory and analysis for LISA sources, and the latest updates on the development of the LISA mission.