© 2020 Background: There are now over 800,000 registered deaths due to the COVID-19 pandemic worldwide. Researchers have suggested that COVID-19 death characteristics (e.g., intensive care admission, unexpected death) and circumstances (e.g., secondary stressors, social isolation) will precipitate a worldwide increase of prolonged grief disorder (PGD) and persistent complex bereavement disorder (PCBD). Yet, no study has investigated this. Since acute grief is a strong predictor of future pathological grief, we compared grief levels among people recently bereaved due to COVID-19, natural, and unnatural causes. Methods: People bereaved through COVID-19 (n = 49), natural causes (n = 1182), and unnatural causes (n = 210), completed self-report measures of demographic and loss-related characteristics and PGD and PCBD symptoms. Results: COVID-19 bereavement yielded higher symptom levels of PGD (d = 0.42) and PCBD (d = 0.35) than natural bereavement (but not unnatural bereavement). Effects held when limiting analyses to recent losses and those who participated during the pandemic. Expectedness of the death explained this effect. Limitations: Limitations include using a convenience sample and self-report measures. Conclusions: Higher grief levels occur among people bereaved due to COVID-19 compared to people bereaved due to natural loss. We predict that pandemic-related increases in pathological grief will become a worldwide public health concern.