Background: Good Grief Festival was originally planned as a face-to-face festival about grief and bereavement. Due to COVID-19, it was held online over 3 days in October 2020. Objective: To evaluate the festival’s reach and impact. Design: Pre/post evaluation Methods: Pre-festival online surveys assessed reasons for attending and attitudes to bereavement across four items (fear of saying the wrong thing, avoiding talking to someone bereaved, knowing what to do if someone bereaved was struggling, knowing how to help). Post-festival online surveys evaluated audience experiences and the four attitude items. Free-text responses, analysed using thematic analysis, generated suggestions for improvement and general comments. Results: Between 5003 and 6438 people attended, with most attending two to five events. Pre-festival survey participants ( n = 3785) were mostly women (91%) and White (91%). About 9% were from Black or minoritised ethnic communities. About 14% were age ⩾65 years, 16% age ⩽34 years. Around 75% were members of the public, teachers, students or ‘other’; 25% academics, clinicians or bereavement counsellors. A third had been bereaved in the last year; 6% had never been bereaved. People attended to learn about grief/bereavement (77%), be inspired (52%) and feel part of a community (49%). Post-festival participants ( n = 685) reported feeling part of a community (68%), learning about grief/bereavement (68%) and being inspired (66%). 89% rated the festival as excellent/very good and 75% agreed that they felt more confident talking about grief after attending. Higher ratings and confidence were associated with attending more events. Post-festival attitudes were improved across all four items ( p < 0.001). Attendees appreciated the festival, particularly valuing the online format, opportunities for connection during lockdown and the diversity and quality of speakers. Suggestions included improving registration, more interactive events and less content. Conclusion: Good Grief Festival successfully reached a large public audience, with benefit in engagement, confidence and community-building. Evaluation was critical in shaping future events. Findings suggest festivals of this nature can play a central role in increasing death- and grief-literacy within a public health approach.