The study aimed to identify the impact of the application of institutional governance principles in the accounting disclosure of service companies listed on the Amman Stock Exchange (ASE). The study collected the financial statements of companies during the period 2014-2019, and the extent of applying the principles of institutional governance was measured through indicators included (board of directors’ size, board of directors’ independence, and concentration of ownership). Accounting disclosure was also measured by return on assets and earnings per share. The study population consisted of service companies listed on the ASE, and the study used the random sample where the number of companies included in the study population (14) companies. The required data was obtained throughout the financial reports of companies published on ASE website as a study sample. The results showed a statistically significant effect on the application of institutional governance principles using their instruments (board of directors’ size, board of directors’ independence, and concentration of ownership) in accounting disclosure (return on assets, earnings per share). In the light of the previous results, the study presented several recommendations, which most importantly: The need to adhere to the principles and rules of institutional governance in a way that assists to protect the rights and interests of shareholders.