Background: COVID-19 vaccine hesitancy has emerged as a major public health challenge. Although med-ical and scientific misinformation has been known to fuel vaccine hesitancy in the past, misinformation surrounding COVID-19 seems to be rampant, and increasing evidence suggests that it is contributing to COVID-19 vaccine hesitancy today. The relationship between misinformation and COVID-19 vaccine hesi-tancy is complex, however, and it is relatively understudied.Methods: In this article, we report qualitative data from two related but distinct studies from a larger pro-ject. Study 1 included semi-structured, open-ended interviews conducted in October-November 2020 via phone with 30 participants to investigate the relationship between misinformation and COVID-19 vac-cine hesitancy. Study 10s results then informed the design of open-ended questions for Study 2, an online survey conducted in May-June 2021 to consider the relationship between misinformation and vaccine hesitancy further. The data were examined with thematic analysis.Results: Study 1 led to the identification of positive and negative themes related to attitudes toward COVID-19 vaccines. In Study 2, responses from vaccine-hesitant participants included six categories of misinformation: medical, scientific, political, media, religious, and technological. Across both Study 1 and Study 2, six vaccine hesitancy themes were identified from the data: concerns about the vaccines' future effects, doubts about the vaccines' effectiveness, commercial profiteering, preference for natural immunity, personal freedom, and COVID-19 denial.Conclusions: The relationship between misinformation and vaccine hesitancy is complicated. Various types of misinformation exist, with each related to a specific type of vaccine hesitancy-related attitude. Personal freedom and COVID-19 denial are vaccine attitudes of particular interest, representing impor-tant yet understudied phenomena. Medical and scientific approaches may not be sufficient to combat misinformation based in religion, media, or politics; and public health officials may benefit from partner-ing with experts from those fields to address harmful misinformation that is driving COVID-19 vaccine hesitancy.(c) 2022 Elsevier Ltd. All rights reserved.