Background: Teaching is central for wider uptake of open science practices.Objective: To evaluate the effects of training for improving open science knowledge among undergraduate students.Method: Undergraduate students taking a health psychology course were given an introductory lecture on open science practices and delivered a group presentation including critical reflection on the implementation of open science practices. Students (npre-training = 95, npost-training = 115) completed questionnaires evaluating pre- and post-training open science knowledge and attitudes.Results: Baseline differences existed between students enrolled in a psychology degree program and students in other programs across most open science knowledge and attitude items. Following the training, students demonstrated improved knowledge about code sharing and user participation. However, study program predicted changes in attitude better than the training.Conclusion: A brief training had small effect on open science knowledge. However, attitude score differences were better explained by students’ disciplinary background.Teaching Implications: A short introduction combined with student activity can enhance students’ knowledge. Longitudinal research is warranted to assess long-term effects of open science training and to investigate whether attitude changes are more latent than changes in knowledge. Students’ pre-existing open science knowledge and attitudes should be considered in open science teaching.