Nowadays,Knowledge Management System (KMS) in the modern bank management system enhances value creation bank performance and fostering their competitive advantage. Despite many benefits of KMS, low acceptance of KMS has been a common problem for successfully implementing KMS in the Bangladeshi banking sector. Therefore, this paper tried to identify the factors that led to the acceptance of Knowledge Management System by extending the UTAUT model to promote value creation. Data were collected from 240 respondents from 15 different branch employees who had used KMS in their daily banking activities in Bangladesh. In the current study, survey data were analysed using Partial Least Square (PLS) method. Our research findings showed that performance expectancy and effort expectancy significantly influenced behaviour intention; on the other hand, social impact has no considerable effect on behaviour intention. The empirical study also revealed that employee facilitating conditions and behaviour intention play a significant role in employees' acceptance behaviour of KMS. Therefore, the current findings of this paper will enrich KMS adoption and value creation literature. This study has confirmed the applicability of the extended UTAUT model in the context of KMS acceptance behaviour among employees for value creation performance. It will also help Bangladeshi bank owners take proper initiative to emphasize this specific area. As a result, the employee can use KMS frequently for improving the organizational outcome.