In the current post-truth era, the ability to assess the reliability of information is an essential citizenship attribute. With nearly half of the present internet traffic estimated to be generated by bots, and misinformation being regularly weaponised by numerous parties for economic or political gain, it is imperative that citizens are equipped with the tools to discriminate facts from fiction, particularly for health- and science-related matters. The present study reports the results of a survey (n = 776) carried out to evaluate susceptibility to scientific misinformation and perception of news source reliability amongst students in an English secondary school. Two distinct scores were developed in order to differentially measure susceptibility to disinformation (i.e. deliberately false information) and unintentional misinformation (i.e. getting the facts wrong). Non-parametric analysis indicated that students’ misinformation (as measured by both scores) decreased significantly over the course of the 5 years of secondary education. Interestingly, the adolescents who took part in the survey exhibited considerably lower belief in common science-based conspiracy theories than the levels previously reported among British adults. Students indicated teachers as their most frequent choice of scientific news. While social media were also indicated as common news sources, students expressed awareness of the unreliability of the content available on social media. Analysis of the open answers indicated that students considered BBC as the most trustworthy source of scientific information, and TikTok as the least trustworthy.