EXAONE 3.5 is a series of artificial intelligence models released by LG AI Research, renowned for their outstanding performance and cost-effectiveness. They excel in training efficiency, contamination mitigation, long text comprehension, and instruction-following abilities. The development of the EXAONE 3.5 model adheres to LG's AI ethics principles and includes an AI ethical impact assessment to ensure responsible usage. The release of these models aims to advance AI research and the ecosystem while laying a foundation for AI innovations.