STATO is a general-purpose STATistics Ontology. Its aim is to provide coverage for processes such as statistical tests, their conditions of applications, and information needed or resulting from statistical methods, such as probability distributions, variable, spread and variation metrics. STATO also covers aspects of experimental design and description of plots and graphical representations commonly used to provide visual cues of data distribution or layout and to assist review of the results. Started in early 2012, as part of the requirement of the community-driven ISA Commons [1, 2] to represent data matrices and their statistical values, STATO is a standalone projects since Nov 2012. STATO is driven and funded by several ISA-based projects and their user community, but also by collaborations with data publication platforms [e.g. 3, 4]. STATO is applicable to, but not limited, the broad life, natural and biomedical science domain with documented applications for factorial design, association studies, differential expression, hit selection and meta-analysis. STATO also benefits from: (i) extensive documentation with the provision of textual and formal definitions; (ii) an associated R code snippets using the dedicated R-command metadata tag, aiming at facilitating teaching and learning while relying of the popular R language; (iii) query examples documentation, highlighting how the ontology can be harnessed for reviewers/tutors/student alike.