Online peer feedback is an effective instructional strategy to enhance students' learning processes and outcomes. However, the literature lacks a comprehensive understanding of the influential factors that play a key role in the effective implementation of online peer feedback. This systematic review provides an overview of the current state of online peer feedback implementation in higher education contexts and explores the role of students' characteristics and online learning environments in relation to their learning processes and outcomes. To achieve this goal, the PRISMA method was followed, and a coding scheme was developed to create a framework that can guide the implementation of online peer feedback in higher education settings. This framework depicts factors that should be taken into account for effective implementation of online peer feedback in terms of four dimensions: students' characteristics (demographic characteristics, academic background, and personality and psychological features), environmental conditions (learning platform and setting), learning processes (content, feedback activity design, and technology), and learning outcomes including cognitive outcomes (e.g., acquisition of knowledge, comprehension, application, analysis, synthesis, and evaluation), behavioral outcomes (engagement, communication, and teamwork), and affective outcomes (satisfaction, motivation, attitude, self-efficacy, sense of autonomy, and confidence). We conclude this study by discussing the framework, limitations, and ideas for future research and practice.