MEs have been a significant driver of Malaysia's economy. SMEs provide opportunities for business expansion and employment for people in need. Therefore, it is important to understand the workforce now as well as in the future. According to earlier studies by others, businesses are currently aggressively seeking the best employees on the market as well as the talent that will eventually replace the ageing baby boomer generation in the upcoming few years. It is because one of their biggest talent concerns is how difficult it is to attract and retain younger employees, especially for millennials and generation Z. The purpose of this study is to examine the factors affecting employee retention among SMEs' millennial employees in the Klang Valley. Three independent variables: career development opportunities, compensation, and workplace flexibility, were selected to examine the relationship with employee retention. The Klang Valley region was chosen as it is the fastest-growing area in Malaysia with a variety of businesses, educational institutions, and entertainment that attract people from all over the nation to these economic hubs. The quantitative research was used for this study. In this study, three data analysis models have been applied in data analysis descriptive analysis, multiple linear regression, and Pearson correlation coefficient analysis. A total of 384 responses were received for data analysis. The research approach was by survey questionnaires via Google Forms and all the data collected will be analysed by IBM SPSS version 28.0.0.0 throughout the pilot test and final analysis. The findings demonstrate that all the three hypotheses were supported. All the independent variables (career development opportunities, compensation, and workplace flexibility) are found to have a significant positive relationship with the dependent variable. Finally, a summary of the main discussion, implication of the study, its limitations, and some recommendations for future study are mentioned in this paper.