This book constitutes the refereed proceedings of the 21st China Conference on Machine Translation, CCMT 2025, which took place in Lanzhou, China, during September 26–28, 2025.The 6 full papers included in this book were carefully reviewed and selected from 6 submissions. The conference has been a highly productive forum for progress in this area and is considered a leading and important academic event in the natural language processing field in China.

This book constitutes the refereed proceedings of the 21st China Conference on Machine Translation, CCMT 2025, which took place in Lanzhou, China, during September 26–28, 2025.The 6 full papers included in this book were carefully reviewed and selected from 6 submissions. The conference has been a highly productive forum for progress in this area and is considered a leading and important academic event in the natural language processing field in China.