I. Executive summary The Austrian Science Fund (FWF), which is Austria's main funding organisation for basic research, encourages and helps all project leaders and project staff members to make their peer-reviewed research results freely available on the Internet. Any exceptions must be clearly indicated and justified. For projects that started after 1 January 2015, open access has been compulsory for all peer-reviewed publications. All principal investigators in FWF-funded projects are obliged to submit a final report within four months of completing their projects. In 2023, a total of 560 final reports were submitted to the FWF, 36 of which could not report any publications so far. The publications and other data mentioned in those reports are archived and analysed by the FWF. This report examines the state of compliance with open access requirements for peer-reviewed publications on the basis of final project reports submitted in the year 2023. Main findings: -A total of 6.389 publications were listed in the final project reports submitted in 2023. -Of those publications, 5.296 were conclusively identified as peer-reviewed. -Regarding compliance with the FWF's Open Access Policy, the analysis shows that 84% of the peer-reviewed publications listed in the final project reports submitted in 2023 were openly accessible (2017: 90%, 2018: 92%, 2019: 89%, 2020: 84%, 2021: 82%, 2022: 85%). -The most frequently chosen option was hybrid open access (37%). The share of gold open access was 31%, the share of green open access 17%, and no open access 16%. -The majority of peer-reviewed publications submitted were journal articles (85%), 91% of which were openly accessible. -The lowest rate of compliance with the FWF's Open Access Policy could be found in editions, contributions to edited volumes, and monographs (34%). -The absolute number of publications listed in final reports in 2023 included 265 publications that were mentioned several times in different projects; however, those repetitions did not affect the relative share of open access publications (84%). II. Bias Most of the publications were submitted to the FWF via a research documentation system (provided by ©Researchfish), in which FWF-funded researchers are able to enter and update their research data on an ongoing basis. The last check of the open access status was performed in March 2024. In some cases, the embargo period may have already expired, and publications labelled ‘closed’ in the FWF’s database may now be accessible through green open access. Whenever the status ‘peer-reviewed’ could not be clearly identified according to the FWF’s guidelines, the publications were classified as non-peer reviewed. Openly available non-peer reviewed publications were entered as 'openly available’.