Open Source Software (OSS) has gained high relevance in the economy, being integrated and used in a wide array of software and services. However, selecting and evaluating the quality of OSS remains challenging for companies. Such a selection decision is difficult, especially for small and medium-sized enterprises (SMEs) with limited resources. Even though researchers have put significant effort into developing solutions to guide the selection of OSS, there is little or no adoption of those approaches in practice. The existing OSS selection frameworks fail to offer intuitive suggestions based on a framework-supported evaluation approach. This Design Science Research-based master thesis presents the OSS Quality Evaluation Framework (OSSQEF) as a potential solution to address the limitations of current approaches for evaluating OSS quality. The OSSQEF provides a systematic approach to evaluate the quality of OSS projects. The 14 incorporated OSS quality criteria have been synthesized from existing scientific publications and further validated and enriched through the input of OSS experts. Thus, this study considered both the scientific and the practitioner perspectives. A literature review was elaborated to assess the scientific perspective, while feedback from OSS practitioners was collected by conducting a qualitative online survey.