This research is designed to investigate the effect of the Sustained Silent Reading strategy on grade nine students' reading comprehension. In addition, it intends to measure its effectiveness on students' reading self-efficacy beliefs. The study addresses the following questions: 1- What is the effect of Sustained Silent Reading on ninth grade students' reading comprehension? 2- What is the effect of Sustained Silent Reading on ninth grade students' reading self- efficacy beliefs? A quasi-experimental design was adopted to address the current research questions. [A Framework for Building a Thoughtful and Engaged Learner, based on the original SSR guidelines recommended by McCracken (1971) and Bandura's Social Learning Theory (1977) along with some implications for practice suggested by Gray (2012) was used for the intervention.] The sample involved 39 students divided into an experimental group, which was given SSR and a control group, which was taught in the usual Extensive Reading program currently employed in cycle 2 and post basic schools in Oman. Data was collected by administering pre- and post-reading comprehension tests and a pre- and post-reading self-efficacy beliefs scale during eight weeks of intervention. The study revealed that there was a positive effect of SSR on grade nine students' reading comprehension. Likewise, both cognitive aspects, and behavioral aspects of the reading self- efficacy beliefs increased in the experimental group. In light of the research findings, some recommendations for practice and for further studies were outlined. Results of this study may have implications that inspire the Ministry of Education to adopt SSR as an alternative program to the extensive reading program currently applied. In addition, it adds to the growing knowledge on students' reading comprehension skills and reading self-efficacy beliefs.