This study explores self-assessment (SA) practices and perceptions among primary school English as a foreign language (EFL) teachers in China. Data were collected through a qualitative web-based questionnaire from 97 EFL teachers in primary public schools across Shanghai, Shenzhen, and Jiangsu. The results indicated a general consensus among teachers on the value of SA for improving student learning and teaching practice. However, current implementation practices appeared less promising, with many teachers employing it infrequently and primarily using it as a measurement tool. Factors influencing their SA implementation were also identified, including students' age and learning ability, effective assessment criteria, large class sizes, exam-oriented culture, sufficient professional knowledge and skills, and parental support. This study suggests that despite most teachers having a positive perception of SA, there is room for improvement in their practices, with a need to promote more regular and formative use of SA. Also, this study underscores the importance of addressing factors affecting the implementation of SA into teaching practices in the Chinese educational context.