Feedback provided by peer reviewers plays a pivotal role in any journal peer-review model. Peer-review feedback helps authors reconsider their manuscripts in a new light and improve their work before it is published. While there is a wealth of knowledge and empirical evidence focusing on effective feedback practices in educational settings, there is a dearth of research on journal peer-review feedback, especially in some academic disciplines including the social sciences and education. To better understand 'good' and 'bad' peer-review feedback practices across academic disciplines, we conducted a systematic literature review, informed by grounded theory, that aimed to identify the feedback features and factors that exert an impact on quality of peer-review feedback. Findings from 20 publications indicate a list of good and bad features of peer-review feedback pertaining to content, language, tone, structure and timeliness. We also identified a number of internal and external factors that influence how peer reviewers provide feedback such as academics' expertise, language skills, motivation and seniority, as well as external influences such as anonymity in peer-review, and interactions between editors and peer reviewers. Implications for researching and practising peer-review are discussed.