Context: Software development has been characterized by two major approaches in the last decade: Agile Software Development aiming at increased velocity and flexibility during the development process and User-Centered Design putting the goals and needs of the system’s end-users in the development focus to deliver software with appropriate usability. Hybrid development models, summarized as User-Centered Agile Software Development (UCASD) in this article, propose to combine the merits of both approaches to design software that is both useful and usable. Objective: This paper aims at capturing the current state of the art in UCASD approaches and deriving generic principles from these approaches. More specifically, we are investigating the following research question: Which principles constitute a user-centered agile software development approach? Method: A systematic review of the literature in UCASD is performed. Identified works are analyzed using a coding scheme that differentiates four integration levels: process, practices, people and technology. Through subsequent synthesis of the identified codes, generic principles of UCASD are derived. Results: We identified and analyzed 83 relevant publications. The analysis resulted in a differentiated coding system and five principles for UCASD: (1) Separate Product Discovery and Product Creation, (2) Iterative and Incremental Design and Development, (3) Parallel Interwoven Creation Tracks, (4) Continuous Stakeholder Involvement, and (5) Artifact-Mediated Communication. Conclusion: Through the results of our paper, we intend to contribute to the Software Development body of knowledge by (1) providing a broad overview of existing works in the area of UCASD, (2) deriving an analysis framework (in form a coding system) for works in this area, going beyond former classifications, and (3) identifying generic principles of UCASD and associating them with specific practices and processes.