In today's economy, companies try to publicize their good value by revealing related information in their financial reports as a way of convincing their stakeholders that investment in them is a good move. This paper delves into the relationship that exists between characteristics of corporate governance and structure of ownership on voluntary disclosure in interim financial reports (half yearly) published, focusing on variables that affect voluntary disclosure of the ASE Jordanian listed companies. The dynamic panel system GMM estimation was employed on the data from 72 selected ASE listed companies for the period of 2009-2013, and the results show that a substantial degree of voluntary disclosure is demonstrated in high level corporate governance awareness and implementation in Jordan. Specifically, the factors of board compensation, audit firm size, and government ownership significantly impact voluntary disclosure. Aside from that, voluntary disclosure in the half-yearly reports has potential impact on market capitalization.