Background Veterinarians report high levels of psychological distress and self-criticism. However, there is minimal research investigating psychological interventions for veterinarians. Evidence suggests that compassion-focused therapy is effective at reducing distress in those with high self-criticism. This study aimed to investigate the feasibility and preliminary effectiveness of a 2-week online compassionate imagery intervention for veterinarians. Methods A one-group repeated measures design was used with 128 veterinarians. Participants completed measures of perfectionism, self-criticism, self-reassurance and fears of compassion four times, at 2-week intervals (at baseline, pre-intervention, post-intervention and 2-week follow-up). Participants answered written questions about their intervention experience post-intervention. Results Content analysis of the qualitative data found the intervention to be acceptable and beneficial to participants. Overall, study attrition was 50.8%, which is reasonable for a low-cost intervention. Minimal differences were found between participants who dropped out compared to those who completed the intervention. Perfectionism, work-related rumination and self-criticism were significantly reduced post-intervention, and these effects were maintained at follow-up. Resilience and self-reassurance remained unchanged. Fears of compassion reduced over the baseline period and pre-post intervention, questioning the validity of the measure. Conclusion Overall, in the context COVID-19, the intervention showed impressive feasibility and preliminary effectiveness. Randomised control trials are recommended as the next step for research to establish the intervention's effectiveness.