Open data are currently a “hot” topic and are linked to greater openness and transparency in a country. Nowadays governments around the world are posting their datasets on online portals so they can become accessible from anyone. These online portals provide information from areas such as: health, transport, education, environment, politics etc. The rapid development of open data portals makes it necessary to evaluate their accessibility and ease of use. One of the biggest challenges that Open Data Portals face when being evaluated, is delivering a better user experience. Based on what other authors have said in relation to this, these portals still do not provide a good support for non-technical users resulting in an unpleasant experience for them.        Aims: This paper aims to discover problems that users come across when they navigate in a specific open data portal in terms of the feelings and emotions they receive from it. A number of evaluations found within related literature are discussed and then an assessment framework is developed to evaluate the user experience of Open Data Portals. Methodology: Based on the research question, an interpretive paradigm and a qualitative approach have been used to conduct the study. Interviews, observations and questionnaires represent the methods for data collection. An inductive content analysis is applied for the analysis of the qualitative data.  Empirical findings: After interviewing 2 technical users and observing or sending questionnaires to 11 students, 5 dimensions are recognized as having an influence on the experience that a user get when navigating an Open Data Portal. They include: Quality of Data, Accessibility, Interactivity, Complexity and Trust.  Conclusions: The study showed that people encounter difficulties on performing specific tasks because of the lack of support. The data has to be updated and modified to provide quality and accuracy. Improvements are requisite in user engagement and privacy issues. Further research is needed to be done for the application of the proposed framework in a specific Open Data Portal.