This study analyzes research articles about open access (OA) indexed by the Scopus database, published from 2001 to 2015, in order to: (a) propose a categorization scheme about OA; (b) categorize the scientific production about OA; and (c) identify research trends on OA through disciplines at international level over time. The authors used descriptive statistical methods and deductive content analysis using an unconstrained matrix in 347 selected research articles. The most explored themes were found to be "overview, current state, and growth of OA" counting for 98 articles (28.2%), and "awareness, perceptions, and attitudes toward OA" for 75 articles (21.6%). As a conclusion, this study reveals a continuous and growing research interest by the OA community in studies focused on case studies regarding the development or evolution of OA in relation to certain groups, institutions, regions, periods, and how different actors perceive and address the OA movement.