This study explores the mediating role of intention in the relationship between attitude, subjective norm, and perceived behavioral control on turnover intention and actual turnover behavior among employees in the SME service sector in Beijing, China. Drawing on the Theory of Planned Behavior (TPB), we hypothesize that employee attitudes towards their job, the influence of subjective norms, and their perceived control over leaving their job collectively influence their turnover intentions, which in turn affect their actual turnover behavior. Data were collected through a structured questionnaire administered to a sample of SME service sector employees in Beijing. Structural equation modeling (SEM) was employed to test the proposed hypotheses and the mediating effect of intention. The findings reveal that intention significantly mediates the relationship between the three TPB components (attitude, subjective norm, and perceived behavioral control) and turnover behavior. Specifically, employees with negative job attitudes, high subjective norms favoring turnover, and high perceived control over leaving are more likely to form strong turnover intentions, which subsequently lead to actual turnover. These results offer valuable insights for SME management in Beijing on the importance of addressing employee attitudes, norms, and perceived control to mitigate turnover rates. The study contributes to the broader literature on employee turnover by highlighting the critical mediating role of intention and providing a nuanced understanding of the TPB in the context of SME service sectors in China.