Electronic Participation (e-Participation) allows that citizenry to use Information and Communication Technologies (ICT) to take part in the government decision-making process and, consequently, in public policy-making. There are diverse initiatives to achieve e-Participation around the world, but effective participation has not been achieved yet. Additionally, the research in e-Participation is scattered and fragmented, that is why the main research topics in this field are still not defined. This paper aims to show the problems related to e-Participation in a structured way. For this purpose, a systematic literature review was carried out, which allowed identifying problems in e-Participation. Then, those problems were organised and classified into problem areas. Each problem area covers a general topic of e-Participation that needs research. This paper helps to focus on future research around the identified problems in the literature. Therefore, this study allows both driving the research in this field and advancing in the successful implementation of e-Participation initiatives. As a result, eight topics, eighteen problem areas, and seventy-three problems were identified.