Nowadays, the field of just in time and operational excellence are considered a backbone and a critical pillar for many companies in order to achieve the competitive advantages. Consequently, the main aim of this study is to define the impact of just in time system on operational excellence in the (14) manufacturing companies operating at Al –Hussein bin Abdullah II qualified industrial zone (QIZ) in Al-Karak Governorate. The sampling unit and analysis (respondents) included (168) manager and head of divisions at the production and logistic departments, and selected purposely according to their work especially in the just in time system area within the target companies. Thus, the researcher designed a questionnaire including of (25) items to gather the desired data from study sample. This study also used the multiple regression analysis to test the hypotheses. The result of the current study found that the just in time system have a positive impact on the operational excellence in Jordanian industrial companies. According to these results the study recommending that the Jordanian industrial companies must emphasis essentially and mainly on their just in time system consisted of (equipment layout, supplier's quality, Setup time reduction; Pull production) in order to enhance and attain the operational excellence and gain competitive advantage. One of the most limitations is that the current study and its finding applied on the Jordanian industrial companies especially at Al-Karak governorate. Therefore, the results of present study can't generalize on the other sectors. Therefore, there is a need to conduct more studies and research on the other sectors such as food Industry and pharmaceutical industries in order to generalize the results. In addition to, conducting comparative studies with other industrial areas located in Jordan.