A competency framework highlights knowledge, skills, attitudes and values (KSAV) that characterize a given profession, role, training or learning pathway. It also describes the different levels of progression within its specific context: either educational or professional. Competency frameworks serve as shared reference tools that can be used across institutional settings for training design, professional development, recruitment, and credentialling. The Citizen Science Competency framework (CitSci Comp) applies this logic to the field of Participatory Research and Citizen Science (PR/CS), defining the KSAV that characterise researchers and practitioners working in this domain. Organized across 7 competency domains and 34 competencies (currently in validation process by the CS/PR Community), the CitSci Comp provides a structured reference for the full spectrum of KSAV in 4 learning and experience progression levels relevant to the professional practice in PR/CS. This CitSci Comp was designed as part of the endeavour of the European Citizen Science (ECS) project to develop a European Citizen Science Academy (ECS Academy), and more specifically its task to create learning paths for newcomers to citizen science in relation to high policy goals such as the Green Deal and or the Sustainable Development Goals. It was done in collaboration with PATTERN project and as part of doctoral research conducted at the FIRE Doctoral School (Université Paris Cité / Learning Planet Institute, Paris, France). Built on a dialogue between existing competency frameworks reviewed by the PR/CS Community by a Modified Delphi Technique (described below), the CitSci Comp draws on existing JRC competency frameworks such as ResearchComp, the European Competence Framework for Researchers developed by the European Commission, EntreComp, DigComp, and the JRC Competence Frameworks for Policymakers and for Science Education, as well as the UK National Co-Ordinating Centre for Public Engagement (NCCPE) framework called “Public engagement lens on the Vitae Researcher Development Framework”, which provided a public engagement lens, with additional competencies and skills, to an existing framework for researchers (the Vitae RDF). As methodology, this CitSci Comp V0 version is the result of a Modified Delphi process conducted with 163 individuals, including 128 across 18 European Research Area (ERA) countries and 55 from countries beyond ERA. The Modified Delphi method combines the structured, multi-round expert consultation of classical Delphi methodology with participatory and qualitative elements, enabling the inclusion of both novice and experienced voices across diverse institutional, transdisciplinary and geographic contexts. Participants included researchers, practitioners, educators, and policy professionals with varying levels of experience in PR/CS. This Version 0 (V0) represents the pre-validation baseline of the CitSci Comp, prior to the third and final round of consensus validation open to the broader PR/CS community. This version reflects the consolidated output aftert Rounds 1 and 2 of the Modified Delphi process. It also serves as the reference document against which Round 3 validation instruments were designed. This document is published here to ensure full transparency of the iterative development process and to enable comparison with subsequent validated versions. This CitSci Comp can have multiple applications across a wide range of institutional and individual contexts: For training design and curriculum development, to guide and support teachers and educators in creating a syllabus and designing training. The training can be a general introduction to PR/CS or for a specific domain/sub-domain for example. As a Career development guide to assist people who want to become practitioners or researchers in PR/CS to identify the skills that they would like to develop, and plan a career development. To support Organizational capacity mapping, assisting people in organisations who want to start PR/CS activities to identify the competencies that they already have in the organisation, or in developing a job description for a researcher or practitioner that they would like to hire Providing guidance on competency and skills progression (learning paths) throughout a career of professional in the area of PR/CS, for individuals, teams and institutions. Assisting in labeling and sharing open educational resources (OER) in PR/CS, by identifying the domain and level or competency for which it is intended Contributors that wished to be acknowledge will be added.