PurposeLiterature about transparency in public-sector organizations has been attracting the attention of scholars for the last two decades. This study reviews the existing literature with the intention of creating a description of the state of the art, categorized by geographical areas, levels of government, topics, and methodologies.Design/methodology/approachThe authors have developed a structured literature review following a rigorous protocol. The initial search was launched on 25 April 2022 on Scopus and Web of Science, resulting in 3,217 articles. After removing duplicates and studies that did not meet all the inclusion criteria specified in the review protocol, the final sample includes 956 articles from 1991 to 2021.FindingsThe analyses show a considerable increase in studies since 2005, especially in the last two years, when 30% of the publications have been produced. Most of the studies analyze the national/central level of government. Many authors compare different countries, while other scholars focus on specific countries, overall, the USA and the UK. The local level of government has also been widely studied, especially in the Spanish and Chinese contexts. The most frequently used methodologies are quantitative and empirical techniques, and the most common topics are those associated with accountability.Originality/valueThis study uses a huge sample (956 articles over the period 1991–2021), which has never been used before, to examine the literature on transparency. The structured literature review facilitates the identification of gaps that can be filled by future studies. These include analyzing transparency in specific geographical areas like Africa, Asia, and Latin America, studying transparency at different levels of government, especially at the regional and federal levels, and providing comparative studies and case study collections.