Reflective Writing as summative assessment has gained popularity across a wide range of subjects in Higher Education. This systematic review searched three cross-disciplinary databases and analysed twenty-two primary research papers published between 2007 and 2022 to investigate (1) the reasons for setting reflective writing as summative assessment, (2) support offered to students engaging in this kind of assessment, (3) student and (4) staff experiences of reflective writing as summative assessment. Using descriptive coding methodology, the review found reflective writing to be used mainly as part of larger assessment tools in professional degree programmes to foster employability and encourage students to reflect on professional practice. Support was provided through specific frameworks, exemplars, feedback and workshops, and when used to foster the incremental development of reflective writing skills in students led to positive experiences. However, the review also highlights a number of issues relating to lacking assessment literacy among students and staff. Moreover, the personal nature of reflection and power dynamics between students and markers can lead to performative instead of genuine reflection and can call into question the validity of reflective writing as summative assessment.