Drawing on dual-process theories, this study aims to investigate the factors associated with social media users’ acceptance of mental health-related misinformation (MHRM). We conducted a case study of Chinese microblogging Weibo on conversations that emerged following a publicised celebrity suicide of South Korean superstar Sulli. This incident sparked an extensive discussion on mental health issues as Sulli was reported to have suffered from depression prior to her death. Whilst previous studies on users’ information acceptance mainly adopted survey methods, our study employs a mixed-method approach (i.e. computational data collection method, content analysis and statistical analysis), which opens up new directions to utilise secondary social media data. We identified MHRM from the discussions on Weibo and labelled the responses to the misinformation as whether they indicate an acceptance of the MHRM. Binary logistic regression was used to examine the associations of receivers’ acceptance of MHRM with its information features (e.g. number of likes) and information sources (e.g. gender). Inconsistent with previous studies, our findings suggest that MHRM is less likely to be accepted when published by male users, underscoring the context-specific nature of heuristic cues. This study also revealed some novel findings, such as MHRM with more pictures or with more words is less likely to be accepted. A theoretical model was proposed based on the findings, which highlights the importance of heuristic cues and individuals’ pre-existing knowledge in information processing.