Pneumonia is part of Acute Respiratory Infections (ARI) that has high disease burden not only in the infants but also among Indonesian adult workforce. Following data from Indonesia medical trend by marsh mercer in 2023, Acute Respiratory Infections (ARI) and Pneumonia showed significant burden in the workplace and recognized as one of highest cases, medical claim, productivity loss and hospitalization. Despite the availability of the vaccine to prevent Pneumonia, the vaccination utilization remains very low in Indonesia workforce and adult in general (Utomo, 2023). This study is aiming to understand better what are the factors that associated with the workforce’ Pneumonia vaccination intention especially after COVID-19 pandemic. This study adopts (Ajzen, 1991) Theory of Planned Behavior (TPB) in explaining the variables (Attitude, Subjective Norm, Perceived Behavior Control and knowledge) that influencing the vaccination intention among Indonesian workforce. This study applies a convergent parallel study with quantitative data analysis and qualitative data analysis are performed parallelly, followed with data integration as summary. The quantitative data is collected through online survey with non-probability sampling & purposive method. Total 151 adult respondents provided their response. The qualitative data is collected through semi-structured interview with total 5 respondents of key identified stakeholders. This study utilized Partial Least Square Structural Equation Modelling (PLS SEM) as data analysis method for quantitative and Thematic Analysis for qualitative method. The results show that attitude, perceived behavior control and knowledge of Acute Respiratory Infections are positively influenced the Pneumonia vaccination intention while subjective norm is not. This study also found the underlying cause of low preventive measurement like vaccination are due to several reasons like the belief of curative is the basic medical needs in the workplace, providing vaccination coverage is part of talent retain/attract strategy, additional cost burden in providing vaccination coverage. Lower awareness on vaccination benefit in general, diseases burden & Prevention of Pneumonia & ARI are the key blockers of the lower vaccination acceptance as preventive measurement in the workplace setting in Indonesia. Lastly, Influenza Vaccination and mask wearing is the most common preventive measurement that embraced by the employer and the employee. This study contributes the application of Extended Theory Planned Behaviour towards vaccination intention among Indonesia workforce for Pneumonia Vaccine and provide extensive insights and recommendation to the multi stakeholders on the strategy to put prevention through vaccination to tackle the high burden of Acute Respiratory Infection Especially Pneumonia among Indonesia workforce.