The platform Österreich forscht was founded in 2014 with the objectives of (1) connecting citizen science actors in Austria, (2) providing the broadest possible overview of citizen science projects in Austria, and (3) scientifically advancing citizen science as a method. Following the initiative of the platform Österreich forscht, many of the institutions that are active in citizen science joined forces in the Citizen Science Network Austria in 2017, and thus agreed to advance the quality of citizen science in Austria. An important step in this regard was the establishment of transparent criteria for projects wishing to be listed on the platform Österreich forscht. The objective of these criteria is to maintain and further improve the quality of the projects presented on the platform. Between March 2017 and February 2018, a working group of the platform Österreich forscht consisting of representatives from 17 institutions developed criteria that allow for the transparent evaluation of projects applying to be listed on Österreich forscht. This was a multi-stage process, building both on the knowledge of the working group members as well as on feedback repeatedly provided by external experts from the respective research fields. Throughout October 2017, a version of the quality criteria was available for public online consultation on the platform Österreich forscht, so as to incorporate the knowledge of the general public into the criteria as well. The final version of the quality criteria was presented at the 4th Austrian Citizen Science Conference, 1-3 February 2018, at which point the criteria also came into effect. Projects already listed on Österreich forscht can adapt to meet the criteria over the next year. Projects wishing to be newly listed on Österreich forscht must meet these criteria at the point of listing. Where necessary, the quality criteria will be adapted in the future, in order to respond to new challenges and developments. The version number, i.e. which version of the criteria a project corresponds to, will be indicated on the respective project page. The first part of the criteria is primarily aimed at establishing what defines a citizen science project. Here, we decided on a negative list (i.e. projects that are NOT citizen science), in order to be as open as possible to different concepts and disciplines. The criteria in the second part are to be understood as minimum standards which all projects listed on the platform Österreich forscht must fulfil. The evaluation will be carried out by the coordinators of the platform Österreich forscht in consultation with working group members. For the quality criteria working group, the chairs Dr. Florian Heigl and Mag. Daniel Dörler