Background: Gestational diabetes (GDM) is an important risk factor for developing type 2 diabetes (T2DM) later in life. Postpartum screening provides an opportunity for early detection and management of T2DM, but uptake is poor. Aim: To explore barriers to screening from clinicians’ perspectives to guide future interventions to increase uptake. Design and Setting: Systematic review and qualitative synthesis. Method: We assessed qualitative studies included in a previous review, then searched five electronic databases from 2013 to May 2019 for qualitative studies reporting clinicians’ perspectives on postpartum glucose screening after GDM. Study quality was assessed against the Critical Appraisal Skills Programmes checklist. Qualitative data from the studies were analysed using thematic synthesis. Results: We included nine studies, containing views from 187 clinicians from both community and hospital care. Three main themes were identified: difficulties in handover between primary and secondary care (ambiguous roles and communication difficulties), short-term focus in clinical consultations (underplaying risk so as not to overwhelm patients and competing priorities) and patient-centric barriers. Conclusion: We identified barriers to diabetes screening at both system and individual levels. At the system level, clarification of responsibility for testing among healthcare professionals and better systems for recall are needed. These could be achieved through registers, improved clinical protocols, and automatic flagging and prompts within electronic medical records. At the individual level, clinicians should be supported to prioritise the importance of screening within consultations and better educational resources made available for women. Making it more convenient for women to attend may also facilitate screening.