This paper investigates how Finnish upper secondary school students evaluate the rhetorical appeals used in an anti-vaccination online text and the extent to which they are critical or non-critical of the text. The empirical data were collected in 2016 from first-year upper secondary school students (n=200) in Finland. The analytical focus was placed on the classic rhetorical appeals, i.e. logos, ethos and pathos. Most students found the online text convincing due to the writer ́s use of logos-related rhetorical appeals. The critical students recognised more frequently emotion-based appeals, while the non-critical students paid more attention to logos-related appeals, for example, appeals to scientific findings. The students who did not find the text convincing were more analytical and reflective in their responses. The findings indicate that the recognition of different rhetorical strategies helps students also to recognize better the interests advocated by the authors of online texts. The evaluation of rhetorical strategies should therefore be more emphasized in the teaching and learning in upper secondary schools.