Procedures for responding consistently to plagiarism incidents are neither clear-cut nor easily implemented and yet inequitable treatment is intrinsically unfair. Classifying the seriousness of a plagiarism incident is problematic and penalties recommended for a given incident can vary greatly. This paper describes the development and testing of a classification framework for determining the degree of seriousness of a plagiarism incident using four criteria each on a continuum from least to most serious, and then classification into three overall levels. The classification scheme was trialled with academics using hypothetical plagiarism cases. Results suggest that the four criteria are useful and useable, and can assist in decision-making, but that professional development for staff will be required to further improve consistency. The trial also revealed the knowledge and thinking processes of academics that might lead to inconsistent decisions. A sample of the Proforma for determining the seriousness of plagiarism is appended. (Contains 5 tables and 4 figures. The appendix contains: Proforma for Determining the Seriousness of Plagiarism. )