The aim of this study is to examine the socio-economic, institutional, and political factors affecting external audit, with the use of an international comparison. In addition, the effect of external audit on fiscal transparency was analyzed. Although many empirical studies in the literature handle the factors affecting fiscal transparency, there are only a few empirical studies that focus on the factors affecting external audit and the impact of external audits on fiscal transparency. However, there is not one study dealing with the factors affecting external audit through making use of international comparisons. In this study we attempt to discover the factors affecting external audit and examine, using an international comparison, the impact of external audits on fiscal transparency. The Open Budget Survey published by the International Budget Partnership in 2017 was used to measure external audits. In the study, consisting of 115 countries, the effect of democratization level, government debt level, government balance, gross domestic product (GDP) per capita, legislative budget oversight, the SAI's audit diversity and the effect of a judicial model of the SAI on external audit were investigated. The effect of external audit on fiscal transparency is tested for 115 countries using the Two-Stage Least Squares Method (2SLS). According to the analysis, it is determined that the level of democratization, gross domestic product (GDP) per capita, budget oversight of the legislature, audit diversity of supreme audit institution and judicial model of supreme audit institution have significant and positive effects on external audit. It is also determined that external audit has a significant and positive effect on fiscal transparency.