UK Biobank (UKB) is a large-scale, prospective resource offering significant opportunities for mental health research. Data include genetic and biological data, healthcare linkage, and mental health enhancements. Challenges arise from incomplete linkage of some sources and the incomplete coverage for enhancements, which also occur at different times post-baseline. We searched for publications using UKB for mental health research from 2016 to 2023 to describe and inspire future use. Papers were classified by mental health topic, ‘additional’ aspects, and the data used to define the mental health topic. We identified 480 papers, with 338 focusing on mental health disorder topics (affective, anxiety, psychotic, multiple, and transdiagnostic). The most commonly studied disorder was depression (41%). The most common single method of ascertaining mental disorder status was the Mental Health Questionnaire (26%), with genetic risk, for example, using polygenic risk scores, also frequent (21%). Common additional aspects included brain imaging, gene–environment interaction, and the relationship with physical health. The review demonstrates the value of UKB to mental health research. We explore the strengths and weaknesses, producing resources informed by the review. A strength is the flexibility: conventional epidemiological studies are present, but also genomics, imaging, and other tools for understanding mental health. A major weakness is selection effects. UKB continues to hold potential, especially with additional data continuing to become available.