Company’s experienced increasing number of customersand it is considered that company has fulfilled customer expectation. However, it was never investigated whether customer’s reason are company service quality or not. It often happens that gap of knowledge occurs between customer perception and management perception. This research was conducted to determine importance level of mobile service quality in customer perception and management perception and whether there is any gap or not. The assessment includes dimensions of System Service Quality (Efficiency And Effectiveness, Functionality, Integration, Construct Cost, Security),Information Service Quality (Accuracy, Integrity, Usability, Readability), and Customer Service Quality (After-Sales Service, Flexible-Price Policy, Technique Support, Training. This research was conducted at PT.Hutchinson 3 Indonesia (Tri), as one of survived cellular operator among other giant companies in Indonesia.It was determined that, in the customer perception from the highest to the lowest, System Service Quality (SSQ)was 87.18%, Information Service Quality (ISQ)was 82.01% and Customer Service Quality (CSQ)was 80.39%. In the management perception from the highest to the lowest, System Service Quality (SSQ)was 89.67%, Customer Service Quality (CSQ)was 84.58%, and Information Service Quality (ISQ)was 83.96%. Tri management is expected to frequently organize communication/promotion forum and evaluate customer complaint data effectively and efficiently in order to make better planning in the future to meet the importance priority in accordance with customer perception. (2018-05-06)