REPOPSI is an open repository that enables users to freely access and share psychological instruments in Serbian and other languages. It was established in 2020 by the Laboratory for Research of Individual Differences (LIRA) at the University of Belgrade – Faculty of Philosophy. REPOPSI holds psychological measures, scales, tests, and other instruments commonly used in social and behavioral science research. While it is primarily intended for Serbian instruments (that is, instruments translated/adapted into Serbian or originally developed by local scientists), it also documents English and multilingual instruments. REPOPSI is a growing collection – it currently contains around 200 instrument records, half of which are available in both Serbian and English. REPOPSI increases the visibility and availability of psychological instruments in Serbian and prevents overlapping translation efforts. Being a good starting point for any project, REPOPSI helps researchers and students quickly find the materials they need. Bilingual and multilingual instruments it offers have proven to facilitate participation in multi-country research projects. Instruments found in REPOPSI may be used under the Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) license. They can be freely accessed and used without permission for noncommercial purposes, provided instrument authors and translators are cited.