For the appraisal of single-case intervention data, school psychologists have been encouraged to focus most, if not all, of their interpretive weight on the visual inspection of graphed data. However, existing software programs provide practitioners with limited features for systematic visual inspection. R (R Development Core Team, 2014) is a free, open-source, statistical programming language that can be utilized to evaluate single-case data. This article reviews salient aspects of single-case evaluation and visual analysis and provides an introduction into the R programming environment. Strategies for incorporation of the platform into applied practice and school psychology research are also discussed.