Recently, there has been growing awareness of the so-called ‘reproducibility crisis’ which refers to the failure to replicate the findings of many scientific studies. This may arise from the employment of questionable research practices, such as ‘p-hacking’ (conducting many statistical tests, and only reporting significant results), HARKING (hypothesising after the results are known), and outcome switching (promoting secondary outcomes to primary outcomes to fit unexpected results). Open Science practices, which encourage open methodology (including pre-registration of hypotheses and outcomes), open data (in a publicly accessible repository), and open access to publication (including pre-prints), are vital to combatting these. This chapter sets out how Open Science practices can be applied to psychiatric research, including consideration of challenges which can arise, such as how to share data safely and appropriately. The chapter includes an explanation of key principles and constructs, and explains how Open Science practises can be embedded throughout the life-cycle of a project, with practical how-to guides and sign-posting to further resources.