Investment is a driving force of company value creation and it is one of the important contributors to economic growth. In order to make a good investment, relevant and reliable financial information is vital. The production of financial information is regulated by financial reporting standards. Hence, the adopted standards may influence the quality of financial information. The International Financial Reporting Standards(IFRS) is claimed to be of high quality, understandable and enforceable, and it has potential to the production of more comparable information. This consequently facilitates investment decision-making. This study investigates the impact of IFRS adoption on financial information quality and investment efficiency. This study also compares the impact of IFRS between rules and principles-based countries. The findings indicate that financial information quality and investment efficiency are higher after IFRS adoption. Financial information quality is also found to mediate the relationship between IFRS adoption and investment efficiency. The results show that the improvement in financial information quality and investment efficiency is stronger in rules-based countries.